2021年08月, 日本エアロゾル学会論文賞, 日本エアロゾル学会
南光太郎、堅田元喜、北和之、反町篤行、保坂健太郎、五十嵐康人
学会誌・学術雑誌による顕彰

Vertical distribution of airborne microorganisms over forest environments:,A potential source of ice-nucleating bioaerosols
T. Maki; K. Hosaka; K.C. Lee; Y. Kawabata; M. Kajino; M. Uto; K. Kita; Y. Igarashi, Airborne microorganisms transported from forested areas can influence cloud formation by forming ice nuclei. However, the vertical transportation of airborne microorganisms over forested areas is not well understood. We collected aerosols at three heights, [ground (2 m), canopy top (20 m), and above canopy (500 m)] during the summer, fall and winter, to analyze the airborne microbial communities that were distributed vertically over the forest. During summer and fall, the microbial particles maintained similar concentrations in the forest zone,(canopy top and ground) and decreased to 1/10th of the microbial concentration in the above canopy area. The particle concentrations in winter indicated efficient vertical mixing below 500 m. High-throughput DNA sequencing revealed that the airborne microbial communities were composed of terrestrial and phyllospheric,species associated with the degradation of decaying plant litters. Regardless of the three seasons, the above canopy was dominated by atmospheric stress-resistant bacteria from the phyla Actinobacteria and Firmicutes.,Unlike bacteria, the mushroom-type fungal members of Agaricomycetes grew in relative abundance above the canopy, primarily throughout the summer and winter, while mold-type fungal Dothideomycetes species were often found at all three heights during the fall. The Fusarium, Pseudomonas, and Bacillus isolates, which were obtained from air samples at three heights, indicated high activities of ice nucleation in the water-drop freezing., Elsevier Ltd.
Atmospheric Environment, 2023年03月, ［査読有り］

〔主要な業績〕Atmospheric resuspension of insoluble radioactive cesium-bearing particles found in the difficult-to-return area in Fukushima
Peng Tang; Kazuyuki Kita; Yasuhito Igarashi; Yukihiko Satou; Koutarou Hatanaka; Kouji Adachi; Takeshi Kinase; Kazuhiko Ninomiya and Atsushi Shinohara, 責任著者, 東京電力福島第一原子力発電所事故によって、環境中に放出された放射性セシウムの中でも、不溶性セシウム微粒子（CsMP、不溶性放射性粒子、いわゆるセシウムボールなど）は、比放射能が大きく重要である。本研究では、福島県の帰還困難地区内での無人(自動)サンプリングされた大気粒子試料から、CsMPを検出・単離することにより、事故直後にCsMPが土壌等に沈着したあと、現在でも自然に再浮遊することにより大気中に存在しうることを初めて示した。, 福島第一原子力発電所から約25kmの未除染の地点で、2015年、2016年、2018年および2019年に、ハイボリュームエアサンプラーにより大気粒子を捕集した計165個の石英繊維フィルター試料を用い、イメージングプレートにより放射能の高い点を検出し、さらに顕微鏡下で比放射能の高い粒子を単離し、合計15個の粒子について走査型電子顕微鏡観察およびエネルギー分散型X線分光法により、大きさ、形状と元素組成を特定できた。単離された粒子の粒径は平均1.8±0.5μmのほぼ球形で、137Cs放射能は0.35 ± 0.23 Bq/granuleであった。形状および元素組成から、これらがいわゆるtype-AのCsMPであることが同定できた。サンプリング地点周囲の土壌からも、同様のCsMPが多く検出された。本研究でのサンプリングは、周囲に人間活動がほとんどない地点で無人(自動)運転により行われており、人間活動による土壌からの飛散は考えにくい。また、観測地点で土壌粒子の風による飛散が多くおこる春季に、CsMPが検出される頻度が高かった。これらの結果から、頻度は低いものの、土壌等に沈着したCsMPが自然条件下で大気中に再浮遊することが明らかになり、また検出された時の大気137Cs放射能に占める割合が23.9±15.3%と無視できない大きさであることから、その環境影響について考慮する必要があることが示された。なお、2016年、2018年および2019年のCsMP検出個数は同じであり、明確な減少トレンドは見られていない。, 日本地球惑星科学連合
Progress in Earth and Planetary Science, 2022年03月, ［査読有り］

Relationship of 137Cs with Fungal Spore Tracers in the Ambient Aerosols from Fukushima after the 2011 Nuclear Accident
Kawamura K; Kunwar B; Kita K; Hayashi N; Igarashi Y, Even after 7 years of the nuclear accident that occurred in 2011 at the Fukushima Dai-ichi nuclear power plant (F1NPP), high levels of 137Cs have been detected in ambient aerosols from some polluted areas of Fukushima. Higher levels of radionuclides were often observed in the atmosphere during and after rain events. We presume that biological processes such as fungal activity associated with higher relative humidity may be involved with a possible emission of radioactivity to the atmosphere, which was originally emitted from the F1NPP accident and was deposited over the ground, forest, soil, etc. Here, we report, for the first time, relationships of 137Cs and organic tracers of fungal spores (i.e., arabitol, mannitol and trehalose) in the aerosol samples collected from Fukushima, Japan. Although we found twice-higher concentrations of 137Cs at nighttime than at daytime, fungal spore tracers did not show a consistent trend to 137Cs, that is, organic tracers at nighttime were similar with those at daytime or were even higher in daytime. This study has not clearly demonstrated that fungal spores are the important source of high levels of 137Cs at nighttime. The current unclear relationship is probably associated with the sampling strategy (four consecutive days with a sampling on/off program for day/nighttime samples) taken in this campaign, which may have caused a complicated meteorological situation., MDPI
Atmosphere, 2022年03月, ［査読有り］

Reassessment of the radiocesium resuspension flux from contaminated ground surfaces in eastern Japan
Mizuo Kajino; Akira Watanabe; Masahide Ishizuka; Kazuyuki Kita; Yuji Zaizen; Takeshi Kinase; Rikuya Hirai; Kakeru Konnai; Akane Saya; Kazuki Iwaoka; Yoshitaka Shiroma; Hidenao Hasegawa; Naofumi Akata; Masahiro Hosoda; Shinji Tokonami; and Yasuhito Igarashi, Resuspension of 137Cs from the contaminated ground surface to the atmosphere is essential for understanding the environmental behaviors of 137Cs and estimating external and inhalation exposure of residents. Kajino et al. (2016) assessed the 137Cs resuspension flux from bare soil and forest ecosystems in eastern Japan in 2013 using a numerical simulation constrained by surface air concentration measurements. However, the simulation was found to underestimate the observed deposition amounts by 2 orders of magnitude. The reason for this underestimation is that the simulation assumed that resuspended 137Cs is carried by submicron aerosols, which have low deposition rates. Based on the observational indications that soil dust and bioaerosols are the major carriers of resuspended 137Cs, a new simulation is performed with higher deposition rates constrained by both surface concentrations and deposition amounts. In the new estimation, the total areal annual resuspension of 137Cs in 2013 is 25.7 TBq, which is equivalent to 0.96 % of the initial deposition (2.68 PBq). Due to the rapid deposition rates, the annual redeposition amount is also large at 10.6 TBq, approximately 40 % of the resuspended 137Cs. The resuspension rate through the atmosphere (0.96 % yr−1) seems slow, but it (2.6 × 10−5 d−1) may not be negligibly small compared to the actual decreasing trend of the ambient gamma dose rate obtained in Fukushima Prefecture after the radioactive decay of 137Cs plus 134Cs in 2013 is,subtracted (1.0–7.9 × 10−4 d−1): resuspension can account for 1 %–10 % of the decreasing rate due to decontamination and natural decay through land surface processes., the European Geosciences Union, Copernicus Publications
Atmospheric chemistry and physics, 2022年01月, ［査読有り］

温帯落葉広葉樹林から放出されたバイオエアロゾルの輸送過程の数値解析
南 光太郎; 堅田 元喜; 北 和之; 反町 篤行; 保坂 健太郎; 五十嵐 康人, Following the Fukushima Daiichi nuclear power plant accident, it has been recognized that bioaerosols with radioactive cesium may have released from radiologically contaminated forest into the atmosphere. In order to evaluate the above process, the emission rate of bioaerosol was inversely estimated using a numerical model named SOLVEG that includes the processes of emission, deposition, and turbulent transport of aerosols. For the inverse estimation, micrometeorological variables and bioaerosol number concentration and flux were observed at a Japanese temperate broad-leaved forest in summer. By tuning modelled emission rate of bioaerosols from forest floor, its best estimate was obtained at the agreement between calculated and observed concentrations below the canopy. General trends of calculated momentum, heat, and bioaerosol fluxes above the canopy were also reproduced in the simulation. In the numerical experiment without bioaerosol input at the top of atmosphere above the canopy, a certain amount (59%) of bioaerosol flux at the floor released above the canopy top, while the rest of the flux deposited onto both canopy and soil. This potential flux above the canopy top was 2.0±1.8×10^-2 μg m^-2 s^-1, which may correspond to the re-emission rate proposed previously by the chemical transport model., 日本エアロゾル学会
エアロゾル研究, 2020年09月, ［査読有り］

Rain‑induced bioecological resuspension of radiocaesium in a polluted forest in Japan
Kazuyuki Kita; Yasuhito Igarashi; Takeshi Kinase; Naho Hayashi; Masahide Ishizuka; Kouji Adachi; Motoo Koitabashi; Tsuyoshi Thomas Sekiyama; Yuichi Onda, 筆頭著者, It is the conventional understanding that rain removes aerosols from the atmosphere. However, we show additional evidence for rain‑induced aerosol emissions in a forest environment: the occurrence of radiocaesium‑bearing aerosols in a Japanese forest due to rain. We carried out general radioactive aerosol observations in a typical mountainous village area within the exclusion zone in Fukushima prefecture to determine the impacts and major drivers of the resuspension of radiocaesium originating from the nuclear accident in March 2011. We found that rain induces an increase in radiocaesium in the air in forests. With further investigations, we confirmed that the fungal spore sources of resuspended radiocaesium seemed to differ between rainy weather and nonrainy weather. Larger fungal particles (possibly macroconidia) are emitted during rainy conditions than during nonrainy weather, suggesting that splash generation by rain droplets is the major mechanism of the suspension of radiocaesium-bearing mould-like fungi., Nature Research
Scientific Reports, 2020年09月, ［査読有り］

地表面に沈着した放射性セシウムの再飛散フラックス測定の試み　　　　　　　　　　　　　　　
反町 篤行; 北 和之; 南光 太郎; 保坂 健太郎; 堅田 元喜; 五十嵐 康人, (公社)大気環境学会
大気環境学会年会講演要旨集, 2020年09月

Abundances and Microphysical Properties of Light‐Absorbing Iron Oxide and Black Carbon Aerosols Over East Asia and the Arctic
Atsushi Yoshida; Nobuhiro Moteki; Sho Ohata; Tatsuhiro Mori; Makoto Koike; Yutaka Kondo; Hitoshi Matsui; Naga Oshima; Akinori Takami; Kazuyuki Kita, ラスト(シニア)オーサー, Black carbon (BC), brown carbon, and light‐absorbing iron oxides (FeOx) aerosols affect Earth's energy budget through their strong absorption of solar radiation. FeOx aerosols can also affect global biogeochemical cycles through their role as a nutrient for oceanic phytoplankton. However, observational data for these aerosols required for evaluating their effects using global models are scarce, especially for FeOx. Here, we summarize and compare the data sets of BC and FeOx from five ground‐based and three aircraft observation campaigns conducted in the East Asian and Arctic regions during the 2009–2018 period acquired using a modified single‐particle soot photometer. In these campaigns, >80% of FeOx‐containing aerosols in the 170–270 nm FeOx core size range had microphysical features indicating an anthropogenic origin. In every campaign, FeOx, BC, and carbon monoxide were tightly correlated with each other with similar slope to the urban campaigns (around Tokyo), implying the spatiotemporal variation of anthropogenic FeOx emission around northern middle‐to‐high latitudes is similar to those of anthropogenic BC and CO emissions., John Wiley & Sons Pte Ltd
Journal of Geophysical Research - Atmosphere, 2020年06月, ［査読有り］

Enhanced new particle formation above the marine boundary layer over the Yellow Sea: Potential impacts on cloud condensation nuclei
Takegawa N; Seto T; Moteki N; Koike M; Oshima N; Adachi K; Kita K; Takami A; Kondo Y, ©2020. American Geophysical Union. All Rights Reserved. Aircraft measurements of aerosols were conducted over the Yellow Sea and the East China Sea from February 14 to March 10, 2013, during the Aerosol Radiative Forcing in East Asia 2013 Winter campaign. Ground-based measurements of aerosols were also conducted on Fukue Island (32.8°N, 128.7°E), located near the boundary of the Yellow Sea and the East China Sea. The aircraft measurements revealed large increases in particle number concentrations in the nucleation mode (2.5–10 nm and up to ~105 cm−3) at altitudes of ~0.5–3 km over the Yellow Sea. This was attributed to enhanced new particle formation (NPF) above the marine boundary layer over the Yellow Sea. The number ratios of Aitken-mode (10–90 nm) or accumulation-mode (>90 nm) particles to black carbon particles (tracer for primary emissions) were used to quantify the effects of NPF on particle number concentrations. We estimated that NPF increased median Aitken-mode particle number concentrations by an order of magnitude at altitudes of ~1–3 km over the Yellow Sea. Synchronized aircraft and ground-based data suggest that vertical transport of Aitken-mode particles formed over the Yellow Sea led to a large variability in the particle growth events observed on Fukue Island. A shift of sea surface temperature near Fukue Island and the resultant promotion of vertical mixing are probably the key mechanisms responsible for this complex feature. Evolution of accumulation-mode particles was observed farther downwind over the East China Sea, suggesting significant impacts of NPF on the regional distributions of cloud condensation nuclei.
Journal of Geophysical Research: Atmospheres, 2020年05月, ［査読有り］

Concentrations and Size Distributions of Black Carbon in the Surface Snow of Eastern Antarctica in 2011
T. Kinase; K. Adachi; N. Oshima; K. Goto‐Azuma; Y. Ogawa‐Tsukagawa; Y. Kondo; N. Moteki; S. Ohata; T. Mori; M. Hayashi; K. Hara; H. Kawashima; K. Kita, ラスト(シニア)オーサー, Wiley
Journal of Geophysical Research - Atmosphere, 2020年01月, ［査読有り］

森林大気のバイオエアロゾル
牧 輝弥; 北 和之; 保坂 健太郎; 五十嵐 康人
大気化学研究, 2020年, ［査読有り］

福島県内の里山地域における大気中Cs濃度の変遷　　　　　　　　　　　　　　　
五十嵐 康人; 北 和之; 木名瀬 健; 林 奈穂; 南 光太郎; 木村 茉央; 反町 篤行; 大河内 博; 後藤 友里絵; 石塚 正秀; 牧 輝弥; 保坂 健太郎; 羽田野 祐子, (公社)大気環境学会
大気環境学会年会講演要旨集, 2019年09月

放射性セシウムの再飛散・再沈着モデリング　　　　　　　　　　　　　　　
梶野 瑞王; 石塚 正秀; 五十嵐 康人; 北 和之; 財前 祐二; 木名瀬 健; 渡邊 明, (公社)大気環境学会
大気環境学会年会講演要旨集, 2019年09月

Fungal spore involvement in the resuspension of radiocaesium in summer
Yasuhito Igarashi; Kazuyuki Kita; Teruya Maki; Takeshi Kinase; Naho Hayashi; Kentaro Hosaka; Kouji Adachi; Mizuo Kajino; Masahide Ishizuka; Tsuyoshi Thomas Sekiyama; Yuji Zaizen; Chisato Takenaka; Kazuhiko Ninomiya; Hiroshi Okochi; Atsuyuki Sorimachi, We observed the atmospheric resuspension of radiocaesium, derived from the Fukushima Dai-ichi Nuclear Power Plant accident, at Namie, a heavily contaminated area of Fukushima, since 2012. During the survey periods from 2012 to 2015, the activity concentrations of radiocaesium in air ranged from approximately 10(-5) to 10(-2) Bq per m(3) and were higher in the warm season than in the cold season. Electron microscopy showed that the particles collected on filters in summer were predominantly of biological origin (bioaerosols), with which the observed radiocaesium activity concentration varied. We conducted an additional aerosol analysis based on fluorescent optical microscopic observation and high-throughput DNA sequencing technique to identify bioaerosols at Namie in 2015 summer. The concentrations of bioaerosols fluctuated the order of 10(6) particles per m(3), and the phyla Basidiomycota and Ascomycota (true Fungi) accounted for approximately two-thirds of the bioaerosols. Moreover, the fungal spore concentration in air was positively correlated with the radiocaesium concentration at Namie in summer 2016. The bioaerosol emissions from Japanese mixed forests in the temperate zone predominately included fungal cells, which are known to accumulate radiocaesium, and should be considered an important scientific issue that must be addressed., NATURE PUBLISHING GROUP
Scientific Reports, 2019年, ［査読有り］

The seasonal variations of atmospheric ^134,137Cs activity and possible host particles for their resuspension in the contaminated areas of Tsushima and Yamakiya, Fukushima, Japan
Takeshi Kinase; Kazuyuki Kita; Yasuhito Igarashi; Kouji Adachi; Kazuhiko Ninomiya; Atsushi Shinohara; Hiroshi Okochi; Hiroko Ogata; Masahide Ishizuka; Sakae Toyoda; Keita Yamada; Naohiro Yoshida; Yuji Zaizen; Masao Mikami; Hiroyuki Demizu; Yuichi Onda, © 2018, The Author(s). A large quantity of radionuclides was released by the Fukushima Daiichi Nuclear Power Plant accident in March 2011, and those deposited on ground and vegetation could return to the atmosphere through resuspension processes. Although the resuspension has been proposed to occur with wind blow, biomass burning, ecosystem activities, etc., the dominant process in contaminated areas of Fukushima is not fully understood. We have examined the resuspension process of radiocesium (134,137Cs) based on long-term measurements of the atmospheric concentration of radiocesium activity (the radiocesium concentration) at four sites in the contaminated areas of Fukushima as well as the aerosol characteristic observations by scanning electron microscopy (SEM) and the measurement of the biomass burning tracer, levoglucosan. The radiocesium concentrations at all sites showed a similar seasonal variation: low from winter to early spring and high from late spring to early autumn. In late spring, they showed positive peaks that coincided with the wind speed peaks. However, in summer and autumn, they were correlated positively with atmospheric temperature but negatively with wind speed. These results differed from previous studies based on data at urban sites. The difference of radiocesium concentrations at two sites, which are located within a 1 km range but have different degrees of surface contamination, was large from winter to late spring and small in summer and autumn, indicating that resuspension occurs locally and/or that atmospheric radiocesium was not well mixed in winter/spring, and it was opposite in summer/autumn. These results suggest that the resuspension processes and the host particles of the radiocesium resuspension changed seasonally. The SEM analyses showed that the dominant coarse particles in summer and autumn were organic ones, such as pollen, spores, and microorganisms. Biological activities in forest ecosystems can contribute considerably to the radiocesium resuspension in these seasons. During winter and spring, soil, mineral, and vegetation debris were predominant coarse particles in the atmosphere, and the radiocesium resuspension in these seasons can be attributed to the wind blow of these particles. Any proofs that biomass burning had a significant impact on atmospheric radiocesium were not found in the present study. [Figure not available: see fulltext.]., 日本地球惑星科学連合
Progress in Earth and Planetary Science, 2018年12月, ［査読有り］

Vertical profile of tropospheric ozone derived from synergetic retrieval using three different wavelength ranges, UV, IR, and microwave: Sensitivity study for satellite observation
Tomohiro O. Sato; Takao M. Sato; Hideo Sagawa; Katsuyuki Noguchi; Naoko Saitoh; Hitoshi Irie; Kazuyuki Kita; Mona E. Mahani; Koji Zettsu; Ryoichi Imasu; Sachiko Hayashida; Yasuko Kasai, We performed a feasibility study of constraining the vertical profile of the tropospheric ozone by using a synergetic retrieval method on multiple spectra, i.e., ultraviolet (UV), thermal infrared (TIR), and microwave (MW) ranges, measured from space. This work provides, for the first time, a quantitative evaluation of the retrieval sensitivity of the tropospheric ozone by adding the MW measurement to the UV and TIR measurements. Two observation points in East Asia (one in an urban area and one in an ocean area) and two observation times (one during summer and one during winter) were assumed. Geometry of line of sight was nadir down-looking for the UV and TIR measurements, and limb sounding for the MW measurement. The retrieval sensitivities of the ozone profiles in the upper troposphere (UT), middle troposphere (MT), and lowermost troposphere (LMT) were estimated using the degree of freedom for signal (DFS), the pressure of maximum sensitivity, reduction rate of error from the a priori error, and the averaging kernel matrix, derived based on the optimal estimation method. The measurement noise levels were assumed to be the same as those for currently available instruments. The weighting functions for the UV, TIR, and MW ranges were calculated using the SCIATRAN radiative transfer model, the Line-By-Line Radiative Transfer Model (LBLRTM), and the Advanced Model for Atmospheric Terahertz Radiation Analysis and Simulation (AMATERASU), respectively. The DFS value was increased by approximately 96, 23, and 30ĝ ̄% by adding the MW measurements to the combination of UV and TIR measurements in the UT, MT, and LMT regions, respectively. The MW measurement increased the DFS value of the LMT ozone
nevertheless, the MW measurement alone has no sensitivity to the LMT ozone. The pressure of maximum sensitivity value for the LMT ozone was also increased by adding the MW measurement. These findings indicate that better information on LMT ozone can be obtained by adding constraints on the UT and MT ozone from the MW measurement. The results of this study are applicable to the upcoming air-quality monitoring missions, APOLLO, GMAP-Asia, and uvSCOPE., Copernicus GmbH
Atmospheric Measurement Techniques, 2018年03月, ［査読有り］

Atmospheric Activity Concentration of 90Sr and 137Cs after the Fukushima Daiichi Nuclear Accident
Zijian Zhang; Kazuhiko Ninomiya; Yoshiaki Yamaguchi; Kazuyuki Kita; Haruo Tsuruta; Yasuhito Igarashi; Atsushi Shinohara
Environmental Science & Technology, 2018年, ［査読有り］

Characterization of hydrocarbons in aerosols and investigation of biogenic sources as a carrier of radiocesium isotopes
Mayuko Nakagawa; Keita Yamada; Sakae Toyoda; Kazuyuki Kita; Yasuhito Igarashi; Shingo Komatsu; Kentaro Yamada; Naohiro Yoshida, Copyright © 2018 by The Geochemical Society of Japan. In this study, the potential natural sources of secondary radiocesium isotope (134Cs and 137Cs) emissions were investigated, with a focus on n-alkanes, a characteristic bioaerosol compound. Monitoring was performed to obtain a time series of aerosol, samples, from winter 2013 to summer 2014, and size-resolved aerosol samples in 2012 and 2014. Samples were collected from the area heavily contaminated after the Fukushima Daiichi Nuclear Power Plant accident in March 2011. A correlation analysis of radiocesium, n-alkanes, and black carbon concentrations was performed to identify the contributions of aerosols from biogenic and anthropogenic sources. Biogenic n-alkanes exhibited similar concentration ranges except for spring 2014. The continuous input of biogenic n-alkanes is characteristic of a sampling site surrounded by forest, where pollen dispersion increased the concentration of biogenic n-alkanes in spring 2014. On the other hand, anthropogenic n-alkane concentrations were significantly increased in spring and summer 2014 (>50 ng/m3), compared with those prior to winter 2014 (<20 ng/m3). This anthropogenic n-alkane increase represents the beginning of reconstruction near the area. The carbon preference index (CPI) clearly showed biogenic n-alkanes with coarse-sized particles (CPI > 3), and more anthropogenic n-alkanes were contained in fine particle aerosols. Our results showed that radiocesium and biogenic n-alkane concentrations in seasonal and size-resolved aerosol samples have a partially positive correlation, which supports the hypothesis that the secondary emissions of radionuclides occurred in the forested areas., 地球化学会
Geochemical Journal, 2018年, ［査読有り］

福島第一原子力発電所近隣における事故５年後の土壌調査　　　　　　　　　　　　　　　
二宮和彦; 北和之; 篠原厚; 河津賢澄; 箕輪はるか; 大槻勤; 高宮幸一; 木野康志; 小荒井一真; 齊藤敬; 佐藤志彦; 末木啓介; 竹内幸生; 土井妙子; 阿部善也; 稲井優希; 岩本康弘; 上杉正樹; 遠藤暁; 大河内博; 奥村真吾; 小野貴大; 小野﨑晴佳; 勝見尚也; 神田晃充; 金野俊太郎; グエンタットタン; 久保謙哉; 小池裕也; 末岡晃紀; 鈴木正敏; 鈴木健嗣; 鈴木杏菜; 高瀬つぎ子; 髙橋賢臣; 竹中聡汰; 張子見; 中井泉; 長尾誠也; 中村駿介; 南部明弘; 西山純平; 西山雄大; 福田大輔; 藤井健悟; 藤田将史; 宮澤直希; 村野井友; 森口祐一; 谷田貝亜紀代; 山守航平; 横山明彦; 吉田剛; 吉村崇; 渡邊明
KEK Proceedings of the 18th Workshop on Environmental Radioactivity, 2017年07月, ［査読有り］

Use of a size-resolved 1-D resuspension scheme to evaluate resuspended radioactive material associated with mineral dust particles from the ground surface
Masahide Ishizuka; Masao Mikami; Taichu Y. Tanaka; Yasuhito Igarashi; Kazuyuki Kita; Yutaka Yamada; Naohiro Yoshida; Sakae Toyoda; Yukihiko Satou; Takeshi Kinase; Kazuhiko Ninomiya; Atsushi Shinohara, A size-resolved, one-dimensional resuspension scheme for soil particles from the ground surface is proposed to evaluate the concentration"of radioactivity in the atmosphere due to the secondary emission of radioactive material. The particle size distributions of radioactive particles at a sampling point were measured and compared with the results evaluated by the scheme using four different soil textures: sand, loamy sand, sandy loam, and silty loam. For sandy loam and silty loam, the results were in good agreement with the size-resolved atmospheric radioactivity concentrations observed at a school ground in Tsushima District, Namie Town, Fukushima, which was heavily contaminated after the Fukushima Daiichi Nuclear Power Plant accident in March 2011. Though various assumptions were incorporated into both the scheme and.evaluation conditions, this study shows that the proposed scheme can.be applied to evaluate secondary emissions caused by aeolian resuspension of radioactive materials associated with mineral dust particles from the ground surface. The results underscore the importance of taking 'soil texture into account when evaluating the concentrations of resuspended, size-resolved atmospheric radioactivity. (C) 2016 Elsevier Ltd. All rights reserved., ELSEVIER SCI LTD
JOURNAL OF ENVIRONMENTAL RADIOACTIVITY, 2017年01月, ［査読有り］

Rapid isolation method for radioactive strontium using EmporeTM Strontium Rad Disk　　　　　　　　　　　　　　　
Zijian Zhang; Kazuhiko Ninomiya; Naruto Takahashi; Takashi Saito; Kazuyuki Kita; Yoshiaki Yamaguchi; Atsushi Shinohara
J. Nucl. & Radiochem. Sci., 2016年08月, ［査読有り］

Effects of wet deposition on the abundance and size distribution of black carbon in East Asia
Y. Kondo; N. Moteki; N. Oshima; S. Ohata; M. Koike; Y. Shibano; N. Takegawa; K. Kita, An improved understanding of the variations in the mass concentration and size distribution of black carbon (BC) in the free troposphere (FT) over East Asia, where BC emissions are very high, is needed to reliably estimate the radiative forcing of BC in climate models. We measured these parameters and the carbon monoxide (CO) concentration by conducting the Aerosol Radiative Forcing in East Asia (A-FORCE) 2013W aircraft campaign in East Asia in winter 2013 and compared these data with measurements made in the same region in spring 2009. The median BC concentrations in the FT originating from North China (NC) and South China (SC) showed different seasonal variations, which were primarily caused by variations in meteorological conditions. CO concentrations above the background were much higher in SC than in NC in both seasons, suggesting a more active upward transport of CO. In SC, precipitation greatly increased from winter to spring, leading to an increased wet deposition of BC. As a result, the median BC concentration in the FT was highest in SC air in winter. This season and region were optimal for the effective transport of BC from the planetary boundary layer to the FT. The count median diameters of the BC size distributions generally decreased with altitude via wet removal during upward transport. The altitude dependence of the BC size distributions was similar in winter and spring, in accord with the similarity in the BC mixing state. The observed BC concentrations and microphysical properties will be useful for evaluating the performance of climate models., AMER GEOPHYSICAL UNION
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 2016年05月

Influence of the melting temperature on the measurement of the mass concentration and size distribution of black carbon in snow
Takeshi Kinase; Kazuyuki Kita; Yoshimi Tsukagawa-Ogawa; Kumiko Goto-Azuma; Hiroto Kawashima, The influence of temperature and time of snow sample melting on the measurement of mass concentration and size distribution of black carbon (BC) in snow was evaluated experimentally. In the experiments, fresh (Shirouma) and aged (Hakusan) snow samples were melted at different temperatures or at different time lengths, and the BC mass concentration and size distribution in the melted snow samples were measured using a nebulizer and a single-particle soot photometer (SP2). In the experiment where melting temperature was varied, the BC mass concentration in the liquid decreased at a melting temperature of 70 degrees C. This decrease was 8.0% for the Shirouma sample and 46.4% for the Hakusan sample and depended on BC particle size, with a significant decrease found at BC diameters less than 350 nm. A similar decrease in BC mass concentration was found when the Hakusan snow sample that had been melted at 5 degrees C was heated to 70 degrees C. The experiment in which melting time was varied indicated that BC mass concentration in the liquid did not change for the Shirouma sample but decreased significantly with a longer melting time for the Hakusan sample (38.6 %). These results indicate that melting of snow samples at high temperatures or over long time periods can significantly affect the measurement of BC mass and its size distribution, especially for aged snow samples., COPERNICUS GESELLSCHAFT MBH
ATMOSPHERIC MEASUREMENT TECHNIQUES, 2016年, ［査読有り］

Long-term assessment of airborne radiocesium after the,Fukushima nuclear accident: Re-suspension from bare soil and forest,ecosystems
Kajino; M.; Ishizuka; M.; Igarashi; Y.; Kita; K.; Yoshikawa; C. and Inatsu; M., The long-term effect of Cs-137 re-suspension from contaminated soil and forests due to the Fukushima nuclear accident has been quantitatively assessed by numerical simulation, a field experiment on dust emission flux in a contaminated area (town of Namie, Fukushima prefecture), and air concentration measurements inside (Namie) and outside (city of Tsukuba, Ibaraki prefecture) the contaminated area. In order to assess the long-term effect, the full year of 2013 was selected to study just after the start of the field experiments. The Cs-137 concentrations at Namie and Tsukuba were approximately 10(-1)-1 and 10(-2)-10(-1) mBqm(-3), respectively. The observed monthly median concentration at Namie was 1 to 2 orders of magnitude larger than that at Tsukuba. This observed difference between the two sites was consistent with the simulated difference, indicating successful modeling of Cs-137 re-suspension and atmospheric transport. The estimated re-suspension rate was approximately 10(-6) day(-1), which was significantly lower than the decreasing rate of the ambient gamma dose rate in Fukushima prefecture (10(-4)-10(-3) day(-1)) as a result of radioactive decay, migration in the soil and biota, and decontamination. Consequently, re-suspension contributed negligibly in reducing ground radioactivity. The dust emission model could reproduce the air concentration of Cs-137 in winter, whereas the summer air concentration was underestimated by 1 to 2 orders of magnitude. Re-suspension from forests at a constant rate of 10(-7) h(-1), multiplied by the green area fraction, could explain the air concentration of Cs-137 at Namie and its seasonal variation. The simulated contribution of dust resuspension to the air concentration was 0.7-0.9 in the cold season and 0.2-0.4 in the warm season at both sites; the remainder of the contribution was re-suspension from forest. The re-suspension mechanisms, especially through the forest ecosystems, remain unknown. This is the first study that provides a crude estimation of the long-term assessment of radiocesium re-suspension. Additional research activities should investigate the processes/mechanisms governing the re-suspension over the long term. This could be achieved through conducting additional field experiments and numerical simulations., COPERNICUS GESELLSCHAFT MBH
Atmospheric Chemistry and Physics, 2016年, ［査読有り］

空間線量率の変動と気象条件の相関に関する研究　　　　　　　　　　　　　　　
古谷真人; 五十嵐康人; 北和之; 青山智夫; 石塚正秀; 羽田野祐子
KEK Proceedings of the 16th Workshop on Environmental Radioactivity, 2015年03月, ［査読有り］

Variability of aerosol particle number concentrations observed over the western Pacific in the spring of 2009
N. Takegawa; N. Moteki; N. Oshima; M. Koike; K. Kita; A. Shimizu; N. Sugimoto; Y. Kondo, Airborne measurements of aerosols were conducted over the western Pacific in the spring of 2009 during the Aerosol Radiative Forcing in East Asia (A-FORCE) aircraft campaign. The A-FORCE flights intensively covered an important vertical-latitudinal range in the outflow region of East Asia (0-9 km altitude; 27 degrees N-38 degrees N). This paper presents the variability of aerosol particle number concentrations obtained by condensation particle counters and a Single-Particle Soot Photometer (SP2), with the focus on those in the free troposphere. The number concentration data include total condensation nuclei with particle diameters (d(p)) larger than 10nm (total CN10), PM0.17-CN10 (dp similar to 10-130 nm), and SP2 black carbon (N-BC; d(p) similar to 75-850 nm). Large increases in total CN10 that were not associated with NBC were observed in the free troposphere, suggesting influences from new particle formation (NPF). Statistical characteristics of total CN10, PM0.17-CN10, and N-BC in the lower troposphere (LT; 0-3 km), middle troposphere (MT; 3-6 km), and upper troposphere (UT; 6-9 km) are investigated. The correlation between total CN10 and NBC, along with the ratio of PM0.17 to total CN10 and carbon monoxide mixing ratio (CO), is used to interpret the observed variability. The median concentrations of total CN10 and PM0.17-CN10 in the UT were higher than those in the MT by a factor of similar to 1.4 and similar to 1.6, respectively. We attribute the enhancements of CN10 in the UT to NPF. Possible mechanisms affecting NPF in the free troposphere are discussed., AMER GEOPHYSICAL UNION
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 2014年12月

大気中の放射線強度の変動　　　　　　　　　　　　　　　
渡邊 明; 鶴田 治雄; 北 和之; 篠原 厚; 二宮 和彦; 桧垣 正吾, (公社)大気環境学会
大気環境学会年会講演要旨集, 2014年08月

Maximum efficiency in the hydroxyl-radical-based self-cleansing of the troposphere
Franz Rohrer; Keding Lu; Andreas Hofzumahaus; Birger Bohn; Theo Brauers; Chih-Chung Chang; Hendrik Fuchs; Rolf Haeseler; Frank Holland; Min Hu; Kazuyuki Kita; Yutaka Kondo; Xin Li; Shengrong Lou; Andreas Oebel; Min Shao; Limin Zeng; Tong Zhu; Yuanhang Zhang; Andreas Wahner, The removal of trace gases from the troposphere is, in most cases, initialized by reactions with hydroxyl radicals, and the products of these reactions are eventually deposited on the Earth's surface. The concentration of these hydroxyl radicals is therefore a measure of atmospheric self-cleansing. In theory, hydroxyl-radical concentrations can be enhanced by the recycling of some of the reaction products. The only known efficient recycling process involves nitrogen oxide and leads to production of ozone, yet observations in regions with high hydrocarbon and low nitrogen oxide concentrations show substantially elevated hydroxyl-radical concentrations, up to ten times higher than expected. If we normalize observed hydroxyl-radical concentrations to the maximum achievable in model calculations with variable nitrogen oxide concentrations, this photochemical coordinate system uncovers a common feature in almost all of these observations: even in the presence of inadequate amounts of nitrogen oxides, hydroxyl-radical concentrations are enhanced to the theoretical maximum obtainable at very much higher nitrogen oxide concentrations. This means that this important part of the self-cleansing capability of the atmosphere is working at maximum efficiency even in regions with a high burden of biogenic hydrocarbons and low nitrogen oxide concentration. Since these processes do not involve nitrogen oxides, tropospheric ozone production is greatly reduced compared with the expectation from current theory., NATURE PUBLISHING GROUP
NATURE GEOSCIENCE, 2014年08月

Variability of aerosol particle number concentrations observed over the western pacific in the spring of 2009
N. Takegawa; N. Moteki; N. Oshima; M. Koike; K. Kita; A. Shimizu; N. Sugimoto; Y. Kondo, © 2014. American Geophysical Union. All rights reserved. Airborne measurements of aerosols were conducted over the western Pacific in the spring of 2009 during the Aerosol Radiative Forcing in East Asia (A-FORCE) aircraft campaign. The A-FORCE flights intensively covered an important vertical-latitudinal range in the outflow region of East Asia (0–9 km altitude; 27°N–38°N). This paper presents the variability of aerosol particle number concentrations obtained by condensation particle counters and a Single-Particle Soot Photometer (SP2), with the focus on those in the free troposphere. The number concentration data include total condensation nuclei with particle diameters (dp) larger than 10 nm (total CN10), PM0.17-CN10 (dp ~10–130 nm), and SP2 black carbon (NBC; dp ~75–850 nm). Large increases in total CN10 that were not associated with NBC were observed in the free troposphere, suggesting influences from new particle formation (NPF). Statistical characteristics of total CN10, PM0.17-CN10, and NBC in the lower troposphere (LT; 0–3 km), middle troposphere (MT; 3–6 km), and upper troposphere (UT; 6–9 km) are investigated. The correlation between total CN10 and NBC, along with the ratio of PM0.17 to total CN10 and carbon monoxide mixing ratio (CO), is used to interpret the observed variability. The median concentrations of total CN10 and PM0.17-CN10 in the UT were higher than those in the MT by a factor of ~1.4 and ~1.6, respectively. We attribute the enhancements of CN10 in the UT to NPF. Possible mechanisms affecting NPF in the free troposphere are discussed.
Journal of Geophysical Research, 2014年

Effect of surface BRDF of various land cover types on geostationary observations of tropospheric NO2
K. Noguchi; A. Richter; V. Rozanov; A. Rozanov; J. P. Burrows; H. Irie; K. Kita, We investigated the effect of surface reflectance anisotropy, bidirectional reflectance distribution function (BRDF), on satellite retrievals of tropospheric NO2. We assume the geometry of geostationary measurements over Tokyo, which is one of the worst air-polluted regions in East Asia. We calculated air mass factors (AMF) and box AMFs (BAMF) for tropospheric NO2 to evaluate the effect of BRDF by using the radiative transfer model SCIATRAN. To model the BRDF effect, we utilized the Moderate Resolution Imaging Spectroradiometer (MODIS) products (MOD43B1 and MOD43B2), which provide three coefficients to express the RossThick-LiSparse reciprocal model, a semi-empirical and kernel-based model of BRDF. Because BRDF depends on the land cover type, we also utilized the High Resolution Land-Use and Land-Cover Map of the Advanced Land Observing Satellite (ALOS)/Advanced Visible and Near Infrared Radiometer type 2 (AVNIR-2), which classifies the ground pixels over Tokyo into six main types: water, urban, paddy, crop, deciduous forest, and evergreen forest. We first develop an empirical model of the three BRDF coefficients for each land cover type over Tokyo and then apply the model to the calculation of land-cover-type-dependent AMFs and BAMFs. Results show that the variability of AMF among the land types is up to several tens of percent, and if we neglect the reflectance anisotropy, the difference with AMFs based on BRDF reaches 10% or more. The evaluation of the BAMFs calculated shows that not considering BRDF will cause large errors if the concentration of NO2 is high close to the surface, although the importance of BRDF for AMFs decreases for large aerosol optical depth (AOD)., COPERNICUS GESELLSCHAFT MBH
ATMOSPHERIC MEASUREMENT TECHNIQUES, 2014年

Temporal changes in the emissions of CH4 and CO from China estimated from CH4/CO2 and CO/CO2 correlations observed at Hateruma Island
Y. Tohjima; M. Kubo; C. Minejima; H. Mukai; H. Tanimoto; A. Ganshin; S. Maksyutov; K. Katsumata; T. Machida; K. Kita, In situ observation of the atmospheric CO2, CH4, and CO mixing ratios at Hateruma Island (HAT, 24.05 degrees N, 123.80 degrees E) often show synoptic-scale variations with correlative elevations during winter, associated with air transport from the East Asian countries. We examine winter (November-March) trends in Delta CH4 / Delta CO2, Delta CO/ Delta CO2, and Delta CO/ Delta CH4 observed at Hateruma over the period 1999 to 2010. To investigate the relationship between the East Asian emissions and the short-term variations in the atmospheric mixing ratios, we use the FLEXPART Lagrangian particle dispersion model (LPDM). The observed ratios Delta CH4 / Delta CO2 and Delta CO/ Delta CO2 both show an overall gradual decrease over the study period due to a recent rapid increase in fossil fuel consumption in China. We note, however, that the decreasing rates of Delta CH4 / Delta CO2 and Delta CO/ Delta CO2 show gradual decrease and increase, respectively, during the entire observation periods used in this study. The Delta CO/ Delta CH4 slope, on the other hand, shows an increasing trend during 1999-2004 but a decrease during 2005-2010. Calculation of the concentration footprint for the atmospheric observation at HAT by using the FLEXPART LPDM indicates that most of the short-term variations are caused by emission variations from northern and eastern China. Combined with a set of reported emission maps, we have estimated the temporal changes in the annual CH4 and CO emissions from China under the assumption that the estimate of the fossil-fuel-derived CO2 emissions based on the energy statistics are accurate. The estimated annual CH4 emissions, corresponding to nonseasonal sources or anthropogenic sources without rice fields, show a nearly constant value of 39 +/- 7 TgCH(4) yr(-1) during 1998-2002, and then gradually increase to 46 +/- 8 TgCH(4) yr(-1) in 2009/2010. The estimated annual CO emissions increase from 134 +/- 32 TgCO yr(-1) in 1998/1999 to 182 +/- 42 TgCO yr(-1) in 2004/2005, level off after 2005, and then slightly decrease to less than 160 TgCO yr(-1) in 2008-2010., COPERNICUS GESELLSCHAFT MBH
ATMOSPHERIC CHEMISTRY AND PHYSICS, 2014年

DIAL measurement of lower tropospheric ozone over Saga (33.24° N, 130.29° E), Japan, and comparison with a chemistry–climate model
O. Uchino; T. Sakai; T. Nagai; I. Morino; T. Maki; M. Deushi; K. Shibata; M. Kajino; T. Kawasaki; T. Akaho; S. Takubo; H. Okumura; K. Arai; M. Nakazato; T. Matsunaga; T. Yokota; S. Kawakami; K. Kita; Y. Sasano, We have improved an ozone DIfferential Absorption Lidar (DIAL) system, originally developed in March 2010. The improved DIAL system consists of a Nd:YAG laser and a 2 m Raman cell filled with 8.1 x 10(5) Pa of CO2 gas which generate four Stokes lines (276, 287, 299, and 312 nm) of stimulated Raman scattering, and two receiving telescopes with diameters of 49 and 10 cm. Using this system, 44 ozone profiles were observed in the 1-6 km altitude range over Saga (33.24A degrees N, 130.29A degrees E) in 2012. High-ozone layers were observed at around 2 km altitude during April and May. Ozone column amounts within the 1-6 km altitude range were almost constant (19.1 DU on average) from January to March, and increased to 26.7 DU from late April to July. From mid-July through August, ozone column amounts decreased greatly to 14.3 DU because of exchanges of continental and maritime air masses. Then in mid-September they increased again to 22.1 DU within 1-6 km, and subsequently decreased slowly to 17.3 DU, becoming almost constant by December.
The Meteorological Research Institute's chemistry-climate model version 2 (MRI-CCM2) successfully predicted most of these ozone variations with the following exceptions. MRI-CCM2 could not predict the high-ozone volume mixing ratios measured at around 2 km altitude on 5 May and 11 May, possibly in part because emissions were assumed in the model to be constant (climatological data were used). Ozone volume mixing ratios predicted by MRI-CCM2 were low in the 2-6 km range on 7 July and high in the 1-4 km range on 19 July compared with those measured by DIAL., COPERNICUS GESELLSCHAFT MBH
Atmospheric Measurement Techniques, 2014年

放射性物質の土壌と森林からの再飛散
北 和之; 足立 光司; 吉田 尚弘; 豊田 栄; 山田 桂大; 渡邊 明; 鶴田 治雄; 長林 久夫; 篠原 厚; 二宮 和彦; 大河内 洋; 田中 美佐子; 石塚 正秀; 川島 洋人; 大越 聡; 佐藤 睦人; 恩田 裕一; 木名瀬 健; 藤澤 遥; 山口 隆亮; 木野 日美子; 出水 宏幸; 五十嵐 康人; 三上 正男, 公益社団法人 大気環境学会
大気環境学会誌, 2014年

Vertical transport mechanisms of black carbon over East Asia in spring during the A-FORCE aircraft campaign
N. Oshima; M. Koike; Y. Kondo; H. Nakamura; N. Moteki; H. Matsui; N. Takegawa; K. Kita, Mechanisms of vertical transport of black carbon (BC) aerosols and their three-dimensional transport pathways over East Asia in spring were examined through numerical simulations for the Aerosol Radiative Forcing in East Asia (A-FORCE) aircraft campaign in March-April 2009 using a modified version of the Community Multiscale Air Quality (CMAQ) modeling system. The simulations reproduced the spatial distributions of mass concentration of BC and its transport efficiency observed by the A-FORCE campaign reasonably well, including its vertical and latitudinal gradients and dependency on precipitation amount that air parcels experienced during the transport. During the A-FORCE period, two types of pronounced upward BC mass fluxes from the planetary boundary layer (PBL) to the free troposphere were found over northeastern and inland-southern China. Over northeastern China, cyclones with modest precipitation were the primary uplifting mechanism of BC. Over inland-southern China, both cumulus convection and orographic uplifting along the slopes of the Tibetan Plateau played important roles in the upward transport of BC, despite its efficient wet deposition due to a large amount of precipitation supported by an abundant moisture supply by the low-level southerlies. In addition to the midlatitude (35-45 degrees N) eastward outflow within the PBL (21% BC removal by precipitation during transport), the uplifting of BC over northeastern and inland-southern China and the subsequent BC transport by the midlatitude lower tropospheric (50% BC removal) and subtropical (25-35 degrees N) midtropospheric westerlies (67% BC removal), respectively, provided the major transport pathways for BC export from continental East Asia to the Pacific., AMER GEOPHYSICAL UNION
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 2013年12月

固相抽出法を用いたエアダストに含まれる放射性ストロンチウムの分析　　　　　　　　　　　　　　　
張 子見; 柿谷 俊輔; 二宮 和彦; 高橋 成人; 山口 喜郎; 吉村 崇; 齊藤 敬; 北 和之; 鶴田 治雄; 桧垣 正吾; 篠原 厚
Proceedings of the 14th Workshop on Environmental Radioactivity (KEK Proceedings 2013-7), 2013年11月, ［査読有り］

福島市、日立市、丸森町における134Cs, 137Csと7Beの大気中放射能濃度変化　　　　　　　　　　　　　　　
柿谷 俊輔; 張 子見; 二宮 和彦; 高橋 成人; 齊藤 敬; 鶴田 治雄; 渡邊 明; 北 和之; 桧垣 正吾; 篠原厚
Proceedings of the 14th Workshop on Environmental Radioactivity (KEK Proceedings 2013-7), 2013年11月, ［査読有り］

地球科学分野における活動と緊急災害時における研究者の対応
中島 映至; 鶴田 治雄; 滝川 雅之; 森野 悠; 関山 剛; 梶野 瑞王; 渡邊 明; 篠原 厚; 北 和之, Japan Radioisotope Association
Radioisotopes, 2013年10月

大気中放射性物質濃度と降下量変動の特徴　　　　　　　　　　　　　　　
渡辺 明; 桧垣 正吾; 篠原 厚; 鶴田 治雄; 北 和之; 吉田 尚弘, (公社)大気環境学会
大気環境学会年会講演要旨集, 2013年08月

Missing OH source in a suburban environment near Beijing: Observed and modelled OH and HO2 concentrations in summer 2006
K. D. Lu; A. Hofzumahaus; F. Holland; B. Bohn; T. Brauers; H. Fuchs; M. Hu; R. Häseler; K. Kita; Y. Kondo; X. Li; S. R. Lou; A. Oebel; M. Shao; L. M. Zeng; A. Wahner; T. Zhu; Y. H. Zhang; F. Rohrer, Measurements of ambient OH and HO2 radicals were performed by laser induced fluorescence (LIF) during CAREBeijing2006 (Campaigns of Air Quality Research in Beijing and Surrounding Region 2006) at the suburban site Yufa in the south of Beijing in summer 2006. On most days, local air chemistry was influenced by aged air pollution that was advected by a slow, almost stagnant wind from southern regions. Observed daily concentration maxima were in the range of (4-17) × 106 cm-3 for OH and (2-24) × 108 cm-3 for HO2 (including an estimated interference of 25% from RO2). During daytime, OH reactivities were generally high (10-30 s-1) and mainly contributed by observed VOCs and their calculated oxidation products. The comparison of modelled and measured HOx concentrations reveals a systematic underprediction of OH as a function of NO. A large discrepancy of a factor 2.6 is found at the lowest NO concentration encountered (0.1 ppb), whereas the discrepancy becomes insignificant above 1 ppb NO. This study extends similar observations from the Pearl-River Delta (PRD) in South China to a more urban environment. The OH discrepancy at Yufa can be resolved, if NO-independent additional OH recycling is assumed in the model. The postulated Leuven Isoprene Mechanism (LIM) has the potential to explain the gap between modelled and measured OH at Beijing taking into account conservative error estimates, but lacks experimental confirmation. This and the hereby unresolved discrepancy at PRD suggest that other VOCs besides isoprene might be involved in the required, additional OH recycling. Fast primary production of ROx radicals up to 7 ppb h-1 was determined at Beijing which was dominated by the photolysis of O3, HONO, HCHO, and dicarbonyls. For a special case, 20 August, when the plume of Beijing city was encountered, a missing primary HOx source (about 3 ppb h-1) was determined under high NOx conditions similar to other urban areas like Mexico City. CAREBeijing2006 emphasizes the important role of OVOCs as a radical source and sink, and the need for further investigation of the chemical degradation of VOCs in order to better understand radical chemistry in VOC-rich air. © 2013 Author(s).
Atmospheric Chemistry and Physics, 2013年

Measurements of regional-scale aerosol impacts on cloud microphysics over the East China Sea: Possible influences of warm sea surface temperature over the Kuroshio ocean current
M. Koike; N. Takegawa; N. Moteki; Y. Kondo; H. Nakamura; K. Kita; H. Matsui; N. Oshima; M. Kajino; T. Y. Nakajima, Cloud microphysical properties and aerosol concentrations were measured aboard an aircraft over the East China Sea and Yellow Sea in April 2009 during the Aerosol Radiative Forcing in East Asia (A-FORCE) experiment. We sampled stratocumulus and shallow cumulus clouds over the ocean in 9 cases during 7 flights 500-900 km off the east coast of Mainland China. In this study we report aerosol impacts on cloud microphysical properties by focusing on regional characteristics of two key parameters, namely updraft velocity and aerosol size distribution. First, we show that the cloud droplet number concentration (highest 5%, N-c_(max)) correlates well with the accumulation-mode aerosol number concentration (N-a) below the clouds. We then show that Nc_max correlates partly with near-surface stratification evaluated as the difference between the sea surface temperature (SST) and 950-hPa temperature (SST - T-950). Cold air advection from China to the East China Sea was found to bring not only a large number of aerosols but also a dry and cold air mass that destabilized the atmospheric boundary layer, especially over the warm Kuroshio ocean current. Over this high-SST region, greater updraft velocities and hence greater N-c_(max) likely resulted. We hypothesize that the low-level static stability determined by SST and regional-scale airflow modulates both the cloud microphysics (aerosol impact on clouds) and macro-structure of clouds (cloud base and top altitudes, hence cloud liquid water path). Second, we show that not only higher aerosol loading in terms of total aerosol number concentration (N-CN, D > 10 nm) but also larger aerosol mode diameters likely contributed to high N-c during A-FORCE. The mean Nc of 650 +/- 240 cm(- 3) was more than a factor of 2 larger than the global average for clouds influenced by continental sources. A crude estimate of the aerosol-induced cloud albedo radiative forcing is also given., AMER GEOPHYSICAL UNION
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 2012年09月

Size dependence of wet removal of black carbon aerosols during transport from the boundary layer to the free troposphere
N. Moteki; Y. Kondo; N. Oshima; N. Takegawa; M. Koike; K. Kita; H. Matsui; M. Kajino, Size distributions of black carbon (BC) measured by aircraft over East Asia in spring 2009 were highly correlated with BC transport efficiency in air parcels uplifted from the planetary boundary layer to the free troposphere. The average single-particle BC mass decreased with decreasing transport efficiency, which suggests that aerosols containing larger BC mass were removed more efficiently. This is the first successful observation of the size-dependent wet removal of aerosols, qualitatively consistent with the Kohler theory. The size distribution of BC uplifted to the free troposphere with high efficiency was similar to the size distribution of BC in the planetary boundary layer. Conversely, the size distribution of BC uplifted with low efficiency was similar to that of background air in the free troposphere. We conclude that wet removal during upward transport is important in controlling the size distribution of BC in the free troposphere. Citation: Moteki, N., Y. Kondo, N. Oshima, N. Takegawa, M. Koike, K. Kita, H. Matsui, and M. Kajino (2012), Size dependence of wet removal of black carbon aerosols during transport from the boundary layer to the free troposphere, Geophys. Res. Lett., 39, L13802, doi: 10.1029/2012GL052034., AMER GEOPHYSICAL UNION
GEOPHYSICAL RESEARCH LETTERS, 2012年07月

Quantifying the relationship between the measurement precision and specifications of a UV/visible sensor on a geostationary satellite
Hitoshi Irie; Hironobu Iwabuchi; Katsuyuki Noguchi; Yasuko Kasai; Kazuyuki Kita; Hajime Akimoto, To investigate the feasibility of new satellite observations, including air quality (AQ) observations from geostationary (GEO) orbit, it is essential to link the measurement precision (epsilon) with sensor specifications in advance. The present study attempts to formulate the linkage between E and specifications of a UV/visible sensor (signal-to-noise ratio (SNR), full width at half maximum (FWHM) of the slit function, and sampling ratio (SR)) on a GEO satellite. A sophisticated radiative transfer model (JACOSPAR) is used to calculate synthetic radiance spectra that would be measured by a UV/visible sensor observing the atmosphere over Tokyo (35.7 degrees N, 139.7 degrees E) from GEO orbit at 120 degrees E longitude. The spectra, modified according to given sensor specifications, are analyzed by the differential optical absorption spectroscopy technique to estimate the E for slant column densities of O-3 and NO2. We find clear relationships: for example, the e of the O-3 slant column density (molecules cm(-2)) and SNR at 330 nm are linked by the equation log(epsilon) = -1.06 . log(SNR) + 20.71 in the UV region, and the epsilon of the NO2 slant column density and SNR at 450 nm are linked by log(epsilon) = -0.98 . log(SNR) + 18.00, at a FWHM = 0.6 nm (for the Gaussian slit function) and SR = 4. The relationships are mostly independent of other specifications (e.g., horizontal and temporal resolutions), as they affect E primarily through SNR, providing constraints in determining the optimal SNR (and alternatively FWHM and SR) for similar UV/visible sensors dedicated for AQ studies., ELSEVIER SCI LTD
ADVANCES IN SPACE RESEARCH, 2012年06月

A study of BRDF over Tokyo for the spaceborne measurements of atmospheric trace gases
K. Noguchi; A. Richter; J. P. Burrows; H. Irie; K. Kita, In the present study, we aim at developing an empirical model of BRDF over Tokyo, Japan, which is one of the most polluted areas in Asia, to evaluate the effect of the surface albedo on air-pollution monitoring from space. We used the RossThick-LiSparseReciprocal model with MODIS data to retrieve BRDF information. The BRDF had a strong dependence on season and local time, and the magnitude of the seasonal and local time change was up to 50%.. © 2012 SPIE., SPIE
Proceedings of SPIE - The International Society for Optical Engineering, 2012年

Observation and modelling of OH and HO2 concentrations in the Pearl River Delta 2006: a missing OH source in a VOC rich atmosphere
K. D. Lu; F. Rohrer; F. Holland; H. Fuchs; B. Bohn; T. Brauers; C. C. Chang; R. Haeseler; M. Hu; K. Kita; Y. Kondo; X. Li; S. R. Lou; S. Nehr; M. Shao; L. M. Zeng; A. Wahner; Y. H. Zhang; A. Hofzumahaus, Ambient OH and HO2 concentrations were measured by laser induced fluorescence (LIF) during the PRIDE-PRD2006 (Program of Regional Integrated Experiments of Air Quality over the Pearl River Delta, 2006) campaign at a rural site downwind of the megacity of Guangzhou in Southern China. The observed OH concentrations reached daily peak values of (15-26) x 10(6) cm(-3) which are among the highest values so far reported for urban and suburban areas. The observed OH shows a consistent high correlation with j((OD)-D-1) over a broad range of NOx conditions. The correlation cannot be reproduced by model simulations, indicating that OH stabilizing processes are missing in current models. The observed OH exhibited a weak dependence on NOx in contrast to model predictions. While modelled and measured OH agree well at NO mixing ratios above 1 ppb, a continuously increasing underprediction of the observed OH is found towards lower NO concentrations, reaching a factor of 8 at 0.02 ppb NO. A dependence of the modelled-to-measured OH ratio on isoprene cannot be concluded from the PRD data. However, the magnitude of the ratio fits into the isoprene dependent trend that was reported from other campaigns in forested regions. Hofzumahaus et al. (2009) proposed an unknown OH recycling process without NO, in order to explain the high OH levels at PRD in the presence of high VOC reactivity and low NO. Taking a recently discovered interference in the LIF measurement of HO2 into account, the need for an additional HO2 -> OH recycling process persists, but the required source strength may be up to 20% larger than previously determined. Recently postulated isoprene mechanisms by Lelieveld et al. (2008) and Peeters and Muller (2010) lead to significant enhancements of OH expected for PRD, but an underprediction of the observed OH by a factor of two remains at low NO (0.1-0.2 ppb). If the photolysis of hydroperoxy aldehydes from isoprene is as efficient as proposed by Peeters and Muller (2010), the corresponding OH formation at PRD would be more important than the primary OH production from ozone and HONO. While the new isoprene mechanisms need to be confirmed by laboratory experiments, there is probably need for other, so far unidentified chemical processes to explain entirely the high OH levels observed in Southern China., COPERNICUS GESELLSCHAFT MBH
ATMOSPHERIC CHEMISTRY AND PHYSICS, 2012年, ［査読有り］

Measurements of regional-scale aerosol impacts on cloud microphysics over the East China Sea: Possible influences of warm sea surface temperature over the Kuroshio ocean current
M. Koike; N. Takegawa; N. Moteki; Y. Kondo; H. Nakamura; K. Kita; H. Matsui; N. Oshima; M. Kajino; T. Y. Nakajima, Wiley-Blackwell
Journal of Geophysical Research: Atmospheres, 2012年, ［査読有り］

Analysis of ΔO2/ΔCO2 ratios for the pollution events observed at Hateruma Island, Japan
C. Minejima; M. Kubo; Y. Tohjima; H. Yamagishi; Y. Koyama; S. Maksyutov; K. Kita; H. Mukai, Pollution events extracted from the in situ observations of atmospheric CO2 and O-2 mixing ratios at Hateruma Island (HAT, 24A degrees N, 124A degrees E) during the period from October 2006 and December 2008 are examined. The air mass origins for the pollution events are categorized by using back trajectory analysis, and the oxidative ratios (OR = -O-2:CO2 molar exchange ratio) for selected pollution events are calculated. We find that there is a significant difference in the average oxidative ratios between events from China (OR = 1.14 +/- 0.12, n = 25) and Japan/Korea (OR = 1.37 +/- 0.15, n = 16). These values are in a good agreement with the national average oxidative ratios for the emissions from fossil fuel burning and cement production (FFBC) in China (ORFFBC = 1.11 +/- 0.03) and Korea/Japan (ORFFBC = 1.36 +/- 0.02). Compared with the observation, simulations of the atmospheric O-2 and CO2 mixing ratios using Lagrangian particle dispersion models do a good job in reconstructing the average oxidative ratio of the pollution events originating in China but tend to underestimate for events originating in Japan/Korea. A sensitivity test suggests that the simulated atmospheric oxidative ratios at HAT are especially sensitive to changes in Chinese fuel mix., COPERNICUS GESELLSCHAFT MBH
Atmospheric Chemistry and Physics, 2012年

Seasonal variations of the transport of black carbon and carbon monoxide from the Asian continent to the western Pacific in the boundary layer
R. L. Verma; Y. Kondo; N. Oshima; H. Matsui; K. Kita; L. K. Sahu; S. Kato; Y. Kajii; A. Takami; T. Miyakawa, Continuous in situ measurements of the mass concentration of black carbon (BC) aerosols and mixing ratio of carbon monoxide (CO) were made at Cape Hedo on Okinawa Island, Japan, a remote site located in the East China Sea, from March 2008 to May 2009. For the first time, we show temporal variations of BC and CO at Hedo in Asian outflows throughout the year. Annual average concentrations of BC and CO were 0.29 mu g m(-3) and 150 ppbv, respectively. The origins of the observed air masses were determined by using 5-day back trajectories, suggesting that about 51% of the air masses arriving at Hedo were from the Chinese region during spring and winter, while about 78% of air masses were of maritime origin during summer. Because of the more frequent transport of Chinese air to Hedo in spring and winter, the average and background concentrations of BC and CO in these seasons were higher by about a factor of 2 than those in summer and fall. Air masses from north China made the largest contributions to elevating the BC levels at Hedo because of the high BC emission rate and frequency of transport. The observed Delta BC/Delta CO ratio systematically decreased with the decrease in model-calculated transport efficiency (TEBCcal). On the basis of this result, we derive region-specific Delta BC/Delta CO ratios by selecting data with TEBCcal > 80%. The annually averaged Delta BC/Delta CO ratios for air originated from north and south China were 7.0 +/- 3.3 and 7.5 +/- 4.6 ng m(-3) ppbv(-1), respectively, about half the annual BC/CO emission ratio derived from the emission inventory of Zhang et al. (2009). We evaluate the CO emission inventory of Zhang et al. (2009) for China by comparing observed (ground-based and aircraft) and model-calculated CO values. The comparison indicates that the CO emissions from China were underestimated by about a factor of 2., AMER GEOPHYSICAL UNION
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 2011年11月

Comparison of laser-induced fluorescence and chemiluminescence measurements of NO2 at an urban site
Hiroyuki Suzuki; Yuka Miyao; Tomoki Nakayama; Julie K. Pearce; Yutaka Matsumi; Kenshi Takahashi; Kazuyuki Kita; Kenichi Tonokura, In situ measurements of nitrogen dioxide (NO2) concentrations were conducted at an urban site in Tokyo (35 degrees 71'N, 139 degrees 76'E), Japan during the summers of 2007-2009. A chemiluminescence instrument equipped with a molybdenum oxide converter (Mo-CL) and a laser-induced fluorescence (LIF) instrument were used simultaneously for determining the ambient NO2 concentrations. A tight linear correlation between the NO2 concentrations determined by the LIF and Mo-CL techniques was evident except for high ozone concentration periods over 50 ppbv. During the high ozone episodes, correlation plots of the NO2 concentrations between Mo-CL and LIF techniques indicated an overestimation of Mo-CL NO2. To examine in detail the systematic differences between two techniques, a thermal dissociation laser-induced fluorescence (TD-LIF) instrument was employed in the summer of 2009 to measure total peroxy nitrates (Sigma PNIs) and total reactive nitrogen (NOz). We found that the Sigma PNs concentrations correlated well with the discrepancies in NO2 concentrations determined by the Mo-CL and LIF techniques. This result suggests that peroxy nitrate species significantly contribute to the observed interference in the Mo-CL measurements under high O-3 concentrations in our observation at the urban site in Tokyo. (C) 2011 Elsevier Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
ATMOSPHERIC ENVIRONMENT, 2011年11月

A202 大気放射性物質の広域観測と土壌からの再飛散の影響(スペシャル・セッション「放射性物質輸送モデルに関する現状と課題」,一般口頭発表)　　　　　　　　　　　　　　　
北, 和之; 笠原, 理絵; 鶴田, 治雄; 桧垣, 正吾; 吉田, 尚弘; 豊田, 栄; 山田, 桂大; 篠原, 厚; 三上, 正男; 五十嵐, 康人; 恩田, 裕一; 末木, 啓介; 地球科学会; 日本地球惑星科学連合; 放射化学会連携緊急放射性物質サンプリングチーム大気班および分析班, 社団法人日本気象学会
大会講演予講集, 2011年10月

Observation and modelling of OH and HO2 concentrations in the Pearl River Delta 2006: A missing OH source in a VOC rich atmosphere　　　　　　　　　　　　　　　
K. D. Lu; F. Rohrer; F. Holland; H. Fuchs; B. Bohn; T. Brauers; C. C. Chang; R. Häseler; M. Hu; K. Kita; Y.Kondo; X. Li; S. R. Lou; S. Nehr; M. Shao; L. M. Zheng; A. Wahner; Y. H. Zhang; A. Hofzumahaus
Atmospheric Chemistry and Physics-Discussion, 2011年, ［査読有り］

Wet removal of black carbon in Asian outflow: Aerosol Radiative Forcing in East Asia (A-FORCE) aircraft campaign
N. Oshima; Y. Kondo; N. Moteki; N. Takegawa; M. Koike; K. Kita; H. Matsui; M. Kajino; H. Nakamura; J. S. Jung; and Y. J. Kim, The Aerosol Radiative Forcing in East Asia (A-FORCE) aircraft campaign was conducted over East Asia in March-April 2009. During the A-FORCE campaign, 120 vertical profiles of black carbon (BC) and carbon monoxide (CO) were obtained in the planetary boundary layer (PBL) and the free troposphere. This study examines the wet removal of BC in Asian outflow using the A-FORCE data. The concentrations of BC and CO were greatly enhanced in air parcels sampled at 3-6 km in altitude over the Yellow Sea on 30 March 2009, associated with upward transport due to a cyclone with modest amounts of precipitation over northern China. In contrast, high CO concentrations without substantial enhancements of BC concentrations were observed in air parcels sampled at 5-6 km over the East China Sea on 23 April 2009, caused by uplifting due to cumulus convection with large amounts of precipitation over central China. The transport efficiency of BC (TE<
inf>
BC<
/inf>
, namely the fraction of BC particles not removed during transport) in air parcels sampled above 2 km during the entire A-FORCE period decreased primarily with the increase in the precipitation amount that air parcels experienced during vertical transport, although their correlation was modest (r<
sup>
2<
/sup>
= 0.43). TE<
inf>
BC<
/inf>
also depended on the altitude to which air parcels were transported from the PBL and the latitude where they were uplifted locally over source regions. The median values of TE<
inf>
BC<
/inf>
for air parcels originating from northern China (north of 33N) and sampled at 2-4 km and 4-9 km levels were 86% and 49%, respectively, during the A-FORCE period. These median values were systematically greater than the corresponding median values (69% and 32%, respectively) for air parcels originating from southern China (south of 33N). Use of the A-FORCE data set will contribute to the reduction of large uncertainties in wet removal process of BC in global- and regional-scale models. Copyright 2012 by the American Geophysical Union., Blackwell Publishing Ltd
Journal of Geophysical Research, 2011年

Oxidant(O3+NO2) production processes and formation regimes in Beijing
K.Liu; Y.Zhang; H.Su; T.Brausers; C.C.Chou; A.Hofzumahaus; S.C.Liu; K.Kita; Y.Kondo; M.Shao; A.Wahner; J.Wang; X.Wang and T.Zhu, 北京郊外で行われたCARE-BEIJING2006観測キャンペーンにより、北京市域でのオゾン生成プロセスについて、NOx制限領域かNMHC制限領域にあるか観測データに基づいて議論した（窒素酸化物測定を担当）。, AMER GEOPHYSICAL UNION
Journal of Geophysical Research, 2010年04月

Radiative transfer modeling of filter-based measurements of light absorption by particles:Importance of particle size dependent penetration depth
N.Moteki; Y.Kondo; T.Nakayama; K.Kita; L.K.Sahu; T.Ishigai; T.Kinase; and Y.Matsumi, PSAPおよびCOSMOSの２種類のフィルター光吸収計による黒色炭素エアロゾルの質量吸収係数測定データについて、フィルターを含む放射伝達により解釈を行った（PSAPによる黒色炭素エアロゾルを担当）。, ELSEVIER SCI LTD
Journal of Aerosol Science, 2010年04月, ［査読有り］

Amplification of Light Absorption of Black Carbon by Organic Coating
M. Shiraiwa; Y. Kondo; T. Iwamoto; K. Kita, Photo-absorption by black carbon (BC) aerosol is believed to be enhanced by the internal mixing of BC with volatile compounds. We investigate this effect quantitatively with laboratory experiments. Graphite particles are used as a surrogate for BC, with coatings of oleic acid and glycerol. The photo-absorption of coated graphite with known shell and core diameters are directly measured by a photo-acoustic technique. The size distribution and coating thickness are quantified using a single-particle soot photometer (SP2). The absorption is amplified by similar to 30% even with a small coating thickness (shell/core diameter ratio (D-p/D-c) = 1.2). The amplification reaches as high as 2 at D-p/D-c = 2. We calculate the amplification of the absorption using a shell/core model of Mie theory. The model generally reproduces the measured amplification well., TAYLOR & FRANCIS INC
AEROSOL SCIENCE AND TECHNOLOGY, 2010年

Size-dependent correction factors for absorption measurements using filter-based photometers:PSAP and COSMOS
T.Nakayama; Y.Kondo; N.Moteki; L.K.Sahu; T.Kinase; K.Kita; Y.Matsumi, PSAPおよびCOSMOSの２種類のフィルター光吸収計による黒色炭素エアロゾルの質量吸収係数測定値の比較から、エアロゾル粒径が小さいほどフィルターに入り込むことによる誤差が大きく、測定値を補正する必要があることを明らかにした（PSAPによる黒色炭素エアロゾル測定を担当）。, ELSEVIER SCI LTD
Journal of Aerosol Science, 2010年

Atmospheric OH reactivities in the Pearl River Delta - China in summer 2006: measurement and model results
S. Lou; F. Holland; F. Rohrer; K. Lu; B. Bohn; T. Brauers; C. C. Chang; H. Fuchs; R. Haeseler; K. Kita; Y. Kondo; X. Li; M. Shao; L. Zeng; A. Wahner; Y. Zhang; W. Wang; A. Hofzumahaus, Total atmospheric OH reactivities (k(OH)) have been measured as reciprocal OH lifetimes by a newly developed instrument at a rural site in the densely populated Pearl River Delta (PRD) in Southern China in summer 2006. The deployed technique, LP-LIF, uses laser flash photolysis (LP) for artificial OH generation and laser-induced fluorescence (LIF) to measure the time-dependent OH decay in samples of ambient air. The reactivities observed at PRD covered a range from 10 s(-1) to 120 s(-1), indicating a large load of chemical reactants. On average, k(OH) exhibited a pronounced diurnal profile with a mean maximum value of 50 s(-1) at daybreak and a mean minimum value of 20 s(-1) at noon. The comparison of reactivities calculated from measured trace gases with measured k(OH) reveals a missing reactivity of about a factor of 2 at day and night. The reactivity explained by measured trace gases was dominated by anthropogenic pollutants (e. g., CO, NOx, light alkenes and aromatic hydrocarbons) at night, while it was strongly influenced by local, biogenic emissions of isoprene during the day. Box model calculations initialized by measured parameters reproduce the observed OH reactivity well and suggest that the missing reactivity is contributed by unmeasured, secondary chemistry products (mainly aldehydes and ketones) that were photochemically formed by hydrocarbon oxidation. Overall, k(OH) was dominated by organic compounds, which had a maximum contribution of 85% in the afternoon. The paper demonstrates the usefulness of direct reactivity measurements, emphasizes the need for direct measurements of oxygenated organic compounds in atmospheric chemistry studies, and discusses uncertainties of the modelling of OVOC reactivities., COPERNICUS GESELLSCHAFT MBH
ATMOSPHERIC CHEMISTRY AND PHYSICS, 2010年

Amplified Trace Gas Removal in the Troposphere
Andreas Hofzumahaus; Franz Rohrer; Keding Lu; Birger Bohn; Theo Brauers; Chih-Chung Chang; Hendrik Fuchs; Frank Holland; Kazuyuki Kita; Yutaka Kondo; Xin Li; Shengrong Lou; Min Shao; Limin Zeng; Andreas Wahner; Yuanhang Zhang, The degradation of trace gases and pollutants in the troposphere is dominated by their reaction with hydroxyl radicals (OH). The importance of OH rests on its high reactivity, its ubiquitous photochemical production in the sunlit atmosphere, and most importantly on its regeneration in the oxidation chain of the trace gases. In the current understanding, the recycling of OH proceeds through HO2 reacting with NO, thereby forming ozone. A recent field campaign in the Pearl River Delta, China, quantified tropospheric OH and HO2 concentrations and turnover rates by direct measurements. We report that concentrations of OH were three to five times greater than expected, and we propose the existence of a pathway for the regeneration of OH independent of NO, which amplifies the degradation of pollutants without producing ozone., AMER ASSOC ADVANCEMENT SCIENCE
SCIENCE, 2009年06月, ［査読有り］

Variability of submicron aerosol observed at a rural site in Beijing in the summer of 2006
N. Takegawa; T. Miyakawa; M. Kuwata; Y. Kondo; Y. Zhao; S. Han; K. Kita; Y. Miyazaki; Z. Deng; R. Xiao; M. Hu; D. van Pinxteren; H. Herrmann; A. Hofzumahaus; F. Holland; A. Wahner; D. R. Blake; N. Sugimoto; T. Zhu, Ground-based measurements of aerosol and trace gases were conducted at a rural site in Beijing in the summer of 2006 as a part of the Campaigns of Air Quality Research in Beijing and Surrounding Region 2006 (CAREBeijing 2006). The size-resolved chemical composition of submicron aerosol was measured using an Aerodyne quadrupole aerosol mass spectrometer (AMS). The data obtained from 15 August to 10 September 2006 are presented. Meteorological analysis shows that the measurement period can be characterized as a cycle of low wind speed periods over the course of a few days (stagnant periods) followed by rapid advection of clean air from the north./northwest mostly due to passage of a midlatitude cyclone. Mass concentrations of total measured aerosol with diameters less than 1 mu m (total PM1), which is defined as the sum of elemental carbon and nonrefractory components measured by the AMS, were highly variable, ranging from similar to 2 to similar to 100 mu g m(-3). Large variability of the PM1 composition and drastic changes in the sulfate (SO42-) size distribution were observed to be associated with the cycle of stagnant periods and advection of clean air, indicating that both chemical and physical properties of aerosols were significantly altered on a time scale of a few days. We have found the dominance of organic aerosol at lower total PM1 mass loadings and that of SO42- at higher mass loadings, which may have important implications for the PM control strategy in Beijing. Possible factors affecting the evolution of the mass concentration and size distribution of SO42- are discussed., AMER GEOPHYSICAL UNION
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 2009年04月, ［査読有り］

Rapid aerosol particle growth and increase of cloud condensation nucleus activity by secondary aerosol formation and condensation: A case study for regional air pollution in northeastern China
A. Wiedensohler; Y. F. Cheng; A. Nowak; B. Wehner; P. Achtert; M. Berghof; W. Birmili; Z. J. Wu; M. Hu; T. Zhu; N. Takegawa; K. Kita; Y. Kondo; S. R. Lou; A. Hofzumahaus; F. Holland; A. Wahner; S. S. Gunthe; D. Rose; H. Su; U. Poeschl, This study was part of the international field measurement Campaigns of Air Quality Research in Beijing and Surrounding Region 2006 (CAREBeijing-2006). We investigated a new particle formation event in a highly polluted air mass at a regional site south of the megacity Beijing and its impact on the abundance and properties of cloud condensation nuclei (CCN). During the 1-month observation, particle nucleation followed by significant particle growth on a regional scale was observed frequently (similar to 30%), and we chose 23 August 2006 as a representative case study. Secondary aerosol mass was produced continuously, with sulfate, ammonium, and organics as major components. The aerosol mass growth rate was on average 19 mu g m(-3) h(-1) during the late hours of the day. This growth rate was observed several times during the 1-month intensive measurements. The nucleation mode grew very quickly into the size range of CCN, and the CCN size distribution was dominated by the growing nucleation mode ( up to 80% of the total CCN number concentration) and not as usual by the accumulation mode. At water vapor supersaturations of 0.07-0.86%, the CCN number concentrations reached maximum values of 4000-19,000 cm(-3) only 6-14 h after the nucleation event. During particle formation and growth, the effective hygroscopicity parameter kappa increased from about 0.1-0.3 to 0.35-0.5 for particles with diameters of 40-90 nm, but it remained nearly constant at similar to 0.45 for particles with diameters of similar to 190 nm. This result is consistent with aerosol chemical composition data, showing a pronounced increase of sulfate., AMER GEOPHYSICAL UNION
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 2009年04月

Aerosol optical properties observed during Campaign of Air Quality Research in Beijing 2006 (CAREBeijing-2006): Characteristic differences between the inflow and outflow of Beijing city air
R. M. Garland; O. Schmid; A. Nowak; P. Achtert; A. Wiedensohler; S. S. Gunthe; N. Takegawa; K. Kita; Y. Kondo; M. Hu; M. Shao; L. M. Zeng; T. Zhu; M. O. Andreae; U. Poeschl, Ground-based measurements of aerosol optical properties were conducted during Campaign of Air Quality Research in Beijing 2006 (CAREBeijing-2006) (11 August to 9 September 2006) at a suburban site similar to 30 km south of Beijing. Averaged over the measurement campaign (arithmetic mean +/- standard deviation), the total scattering coefficients (sigma(s)) were 469 +/- 374 Mm(-1) (450 nm), 361 +/- 295 Mm(-1) (550 nm), and 249 +/- 206 Mm(-1) (700 nm) and the absorption coefficient (sigma(a)) was 51.8 +/- 36.5 Mm(-1) (532 nm). The average Angstrom exponent was 1.42 +/- 0.19 (450 nm/700 nm) and the average single scattering albedo (w(532)) was 0.86 +/- 0.07 (532 nm) with minimum values as low as 0.5. Pronounced diurnal cycles were observed in sigma(s), sigma(a), and w(532) and can be explained by boundary layer mixing effects. Additionally, an enhancement of absorbing particles in the early morning (0500- 0800 local time) was observed; this may be attributed to soot emissions from traffic activity. When the measured air masses originated in the north and passed over Beijing, the single scattering albedo was generally low (w(532) < 0.8), which indicates that the local emissions of particulate matter in Beijing were dominated by primary particles from combustion sources (soot). The southerly inflow to Beijing had typically very high sigma(s) and higher than average w(532) values, suggesting a large amount of secondary aerosol (e. g., sulfate and oxidized organics). Overall, the results suggest that a majority of the particle pollution in Beijing is transported into the city from the south., AMER GEOPHYSICAL UNION
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 2009年02月, ［査読有り］

Chemical characterization of water-soluble organic carbon aerosols at a rural site in the Pearl River Delta, China, in the summer of 2006
Miyazaki; Y.; Y. Kondo; M. Shiraiwa; N. Takegawa; T. Miyakawa; S. Han; K. Kita; M. Hu; Z. Q. Deng; Y. Zhao; N. Sugimoto; D. R. Blake; and R. J. Weber, Online measurements of water-soluble organic carbon (WSOC) aerosols were made using a particle-into-liquid sampler (PILS) combined with a total organic carbon (TOC) analyzer at a rural site in the Pearl River Delta region, China, in July 2006. A macroporous nonionic (DAX-8) resin was used to quantify hydrophilic and hydrophobic WSOC, which are defined as the fractions of WSOC that penetrated through and retained on the DAX-8 column, respectively. Laboratory calibrations showed that hydrophilic WSOC (WSOCHPI) included low-molecular aliphatic dicarboxylic acids and carbonyls, saccharides, and amines, while hydrophobic WSOC (WSOCHPO) included longer-chain aliphatic dicarboxylic acids and carbonyls, aromatic acids, phenols, organic nitrates, cyclic acids, and fulvic acids. On average, total WSOC (TWSOC) accounted for 60% of OC, and WSOCHPO accounted for 60% of TWSOC. Both WSOCHPI and WSOCHPO increased with photochemical aging determined from the NOx/NOy ratio. In particular, the average WSOCHPO mass was found to increase by a factor of five within a timescale of similar to 10 hours, which was substantially larger than that of WSOCHPI (by a factor of 2-3). The total increase in OC mass with photochemical aging was associated with the large increase in WSOCHPO mass. These results, combined with the laboratory calibrations, suggest that significant amounts of hydrophobic organic compounds (likely containing large carbon numbers) were produced by photochemical processing. By contrast, water-insoluble OC (WIOC) mass did not exhibit significant changes with photochemical aging, suggesting that chemical transformation of WIOC to WSOC was not a dominant process for the production of WSOC during the study period., AMER GEOPHYSICAL UNION
Journal of Geophysical Research, 2009年, ［査読有り］

Spatial and Temporal Variations of Aerosols Around Beijing in the Summer 2006: 1. Model Evaluation and Source Apportionment
Matsui; H.; M. Koike; Y. Kondo; N. Takegawa; K. Kita; Y. Miyazaki; M. Hu; S-Y. Chang; D. R. Blake; J. D. Fast; R. A. Zaveri; D. G. Streets; Q. Zhang; and T. Zhu, Regional aerosol model calculations were made using the Weather Research and Forecasting (WRF)-Community Multiscale Air Quality (CMAQ) and WRF-chem models to study spatial and temporal variations of aerosols around Beijing, China, in the summer of 2006, when the Campaigns of Air Quality Research in Beijing and Surrounding Region 2006 (CAREBeijing) intensive campaign was conducted. Model calculations captured temporal variations of primary ( such as elemental carbon (EC)) and secondary ( such as sulfate) aerosols observed in and around Beijing. The spatial distributions of aerosol optical depth observed by the MODIS satellite sensors were also reproduced over northeast China. Model calculations showed distinct differences in spatial distributions between primary and secondary aerosols in association with synoptic-scale meteorology. Secondary aerosols increased in air around Beijing on a scale of about 1000 x 1000 km(2) under an anticyclonic pressure system. This air mass was transported northward from the high anthropogenic emission area extending south of Beijing with continuous photochemical production. Subsequent cold front passage brought clean air from the north, and polluted air around Beijing was swept to the south of Beijing. This cycle was repeated about once a week and was found to be responsible for observed enhancements/reductions of aerosols at the intensive measurement sites. In contrast to secondary aerosols, the spatial distributions of primary aerosols (EC) reflected those of emissions, resulting in only slight variability despite the changes in synoptic-scale meteorology. In accordance with these results, source apportionment simulations revealed that primary aerosols around Beijing were controlled by emissions within 100 km around Beijing within the preceding 24 h, while emissions as far as 500 km and within the preceding 3 days were found to affect secondary aerosols., AMER GEOPHYSICAL UNION
Journal of Geophysical Research, 2009年, ［査読有り］

Stabilization of the mass absorption cross section of black carbon for filter-based absorption photometry by the use of a heated inlet
Kondo.Y.; L.Sahu; M.Kuwata; Y.Miyazaki; N.Takegawa; NMoteki; J.Imaru; S.Han; T.Nakayamma; N.T.KimOanh; M.Hu; Y.J.Kim and K.Kita, フィルター光吸収計による黒色炭素エアロゾルの質量吸収計数測定値は、インレットを４００℃程度に加熱することで、並存する散乱性物質が揮発するため安定に測定できることを示した（PSAPによる黒色炭素エアロゾル測定を担当）。, TAYLOR & FRANCIS INC
Aerosol Science and Technology, 2009年

Mechanisms that influence the formation of high-ozone regions in the boundary layer downwind of the Asian continent in winter and spring
Y. Kondo; R. C. Hudman; K. Nakamura; M. Koike; G. Chen; Y. Miyazaki; N. Takegawa; D. R. Blake; I. J. Simpson; M. Ko; K. Kita; T. Shirai; S. Kawakami, The seasonal variation of ozone (O-3) in the boundary layer (BL) over the western Pacific is investigated using a chemistry-transport model. The model results for January and April-May 2002 were evaluated by comparison with PEACE aircraft observations. In January, strong northwesterlies efficiently transported NOx from the continent, leading to an O-3 increase of approximately 5-10 ppbv over a distance of about 3000 km. In April, southwesterlies dominated due to anticyclone development over the western Pacific. Along this flow, O-3 continued to be produced by NOx emitted from East Asia. This resulted in the formation of a high-O-3 (> 50 ppbv) region extending along the coastal areas of East Asia. This seasonal change in O-3 was driven in part by a change in the net O-3 production rate due to increases in solar UV and H2O. Its exact response depended on the NOx values in the BL. The net O-3 production rate increased between winter and spring over the Asian continent and decreased over the remote western Pacific. Model simulations show that about 25% of the total O-3 (of 10-20 ppbv) increase over the coastal region of Northeast Asia was due to local production from NOx emissions from China, and the rest was due to changes in background levels as well as emissions from Korea, Japan, and east Siberia. Uplift of BL air over Asia, horizontal transport in the free troposphere, and subsidence were the principal mechanisms of transporting Asian O-3 to the central and eastern North Pacific., AMER GEOPHYSICAL UNION
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 2008年08月, ［査読有り］

Ozone-enhanced layers in the troposphere over the equatorial Pacific Ocean and the influence of transport of midlatitude UT/LS air
H. Hayashi; K. Kita; and S. Taguchi, 責任著者, Occurrence of ozone (O3)-enhanced layers in the troposphere over the equatorial Pacific Ocean and their seasonal variation were investigated based on ozonesonde data obtained at three Southern Hemisphere ADditional OZonesondes (SHADOZ) sites, Watukosek, American Samoa and San Cristobal, for 6 years between 1998 and 2003. O3-enhanced layers were found in about 50% of observed O3 profiles at the three sites on yearly average. The formation processes of O3-enhanced layers were investigated by meteorological analyses including backward trajectories. On numerous occasions, O3-enhanced layers resulted from the transport of air masses affected by biomass burning. The contribution of this process was about 30% at San Cristobal during the periods from February to March and from August to September, while it was relatively low, about 10%, at Watukosek and Samoa. A significant number of the O3-enhanced layers were attributed to the transport of midlatitude upper-troposphere and lower-stratosphere (UT/LS) air., COPERNICUS GESELLSCHAFT MBH
Atmospheric Chemistry and Physics, 2008年05月, ［査読有り］

Atmospheric hydrogen peroxide and organic hydroperoxides during PRIDE-PRD'06, China: their concentration, formation mechanism and contribution to secondary aerosols
W. Hua; Z. M. Chen; C. Y. Jie; Y. Kondo; A. Hofzumahaus; N. Takegawa; C. C. Chang; K. D. Lu; Y. Miyazaki; K. Kita; H. L. Wang; Y. H. Zhang; and M. Hu, Atmospheric hydrogen peroxide (H(2)O(2)) and organic hydroperoxides were measured from 18 to 30 July in 2006 during the PRIDE-PRD'06 campaign at Backgarden, a rural site located 48 km north of Guangzhou, a mega-city in southern China. A ground-based instrument was used as a scrubbing coil collector to sample ambient air, followed by on-site analysis by high-performance liquid chromatography (HPLC) coupled with post-column derivatization and fluorescence detection. The H(2)O(2) mixing ratio over the 13 days ranged from below the detection limit to a maximum of 4.6 ppbv, with a mean (and standard deviation) of (1.26 +/- 1.24) ppbv during the daytime (08:00-20:00 LT). Methyl hydroperoxide (MHP), with a maximum of 0.8 ppbv and a mean (and standard deviation) of (0.28 +/- 0.10) ppbv during the daytime, was the dominant organic hydroperoxide. Other organic peroxides, including bis-hydroxymethyl hydroperoxide (BHMP), peroxyacetic acid (PAA), hydroxymethyl hydroperoxide (HMHP), 1-hydroxy-ethyl hydroperoxide (1-HEHP) and ethyl hydroperoxide (EHP), were detected occasionally. The concentration of H(2)O(2) exhibited a pronounced diurnal variation on sunny days, with a peak mixing ratio in the afternoon (12:00-18:00 LT), but lacked an explicit diurnal cycle on cloudy days. Sometimes a second peak mixing ratio of H(2)O(2) was observed during the evening, suggesting that H(2)O(2) was produced by the ozonolysis of alkenes. The diurnal variation profile of MHP was, in general, consistent with that of H(2)O(2). The estimation indicated that in the morning the H(2)O(2) detected was formed mostly through local photochemical activity, with the rest probably attributable to vertical transport. It is notable that relatively high levels of H(2)O(2) and MHP were found in polluted air. The unexpectedly high level of HO(2) radicals detected in this region can account for the production of hydroperoxides, while the moderate level of NO(x) suppressed the formation of hydroperoxides. High concentrations of hydroperoxides were detected in samples of rainwater collected in a heavy shower on 25 July when a typhoon passed through, indicating that a considerable mixing ratio of hydroperoxides, particularly MHP, resided above the boundary layer, which might be transported on a regional scale and further influence the redistribution of HO(x) and RO(x) radicals. It was found that hydroperoxides, in particular H(2)O(2), play an important role in the formation of secondary sulfate in the aerosol phase, where the heterogeneous reaction might contribute substantially. A negative correlation between hydroperoxides and water-soluble organic compounds (WSOC), a considerable fraction of the secondary organic aerosol (SOA), was observed, possibly providing field evidence for the importance of hydroperoxides in the formation of SOA found in previous laboratory studies. We suggest that hydroperoxides act as an important link between sulfate and organic aerosols, which needs further study and should be considered in current atmospheric models., COPERNICUS PUBLICATIONS
Atmospheric Chemistry and Physics, 2008年, ［査読有り］

Aerosol optical properties in a rural environment near the mega-city Guangzhou, China: implications for regional air pollution, radiative forcing and remote sensing
R. M. Garland; H. Yang; O. Schmid; D. Rose; A. Nowak; P. Achtert; A. Wiedensohler; N. Takegawa; K. Kita; Y. Miyazaki; Y. Kondo; M. Hu; M. Shao; L. M. Zeng; Y. H. Zhang; M. O. Andreae; and U. Pöschl, The scattering and absorption of solar radiation by atmospheric aerosols is a key element of the Earth's radiative energy balance and climate. The optical properties of aerosol particles are, however, highly variable and not well characterized, especially near newly emerging mega-cities. In this study, aerosol optical properties were measured at a rural site approximately 60 km northwest of the mega-city Guangzhou in southeast China. The measurements were part of the PRIDE-PRD2006 intensive campaign, covering the period of 1-30 July 2006. Scattering and absorption coefficients of dry aerosol particles with diameters up to 10 mu m (PM10) were determined with a three-wavelength integrating nephelometer and with a photoacoustic spectrometer, respectively.
Averaged over the measurement campaign (arithmetic mean +/- standard deviation), the total scattering coefficients were 200 +/- 133 Mm(-1) (450 nm), 151 +/- 103 Mm(-1) (550 nm) and 104 +/- 72 Mm(-1) (700 nm) and the absorption coefficient was 34.3 +/- 26.5 Mm-1 (532 nm). The average Angstrom exponent was 1.46 +/- 0.21 (450 nm/700 nm) and the average single scattering albedo was 0.82 +/- 0.07 (532 nm) with minimum values as low as 0.5. The low single scattering albedo values indicate a high abundance, as well as strong sources, of light absorbing carbon (LAC). The ratio of LAC to CO concentration was highly variable throughout the campaign. indicating a complex mix of different combustion sources. The scattering and absorption coefficients, as well as the Angstrom exponent and single scattering albedo, exhibited pronounced diurnal cycles, which can be attributed to boundary layer mixing effects and enhanced nighttime emissions of LAC (diesel soot from regulated truck traffic). The daytime average mid-visible sin-le scattering albedo of 0.87 appears to be more suitable for climate modeling purposes than the 24-h average of 0.82, as the latter value is strongly influenced by fresh emissions into a shallow nocturnal boundary layer. In spite of high photochemical activity during daytime. we found no evidence for strong local production of secondary aerosol mass.
The average mass scattering efficiencies with respect to PM10 and PM1 concentrations derived from particle size distribution measurements were 2.8 m(2) g(-1) and 4.1 m(-2) g(-1), respectively. The Angstrom exponent exhibited a wavelength dependence (curvature) that was related to the ratio of fine and coarse particle mass (PM1/PM10) as well as the surface mode diameter of the fine particle fraction. The results demonstrate consistency between in situ measurements and a remote sensing formalism with regard to the fine particle fraction and volume mode diameter, but there are also systematic deviations for the larger mode diameters. Thus we suggest that more data sets from in situ measurements of aerosol optical parameters and particle size distributions should be used to evaluate formalisms applied in aerosol remote sensing. Moreover, we observed a negative correlation between single scattering albedo and backscatter fraction, and we found that it affects the impact that these parameters have on aerosol radiative forcing efficiency and should he considered in model studies of the PRD and similarly polluted mega-city regions., COPERNICUS GESELLSCHAFT MBH
Atmospherric Chemistry and Physics, 2008年, ［査読有り］

Seasonal variations of atmospheric C2–C7 nonmethane hydrocarbons in Tokyo
Tomoko Shirai; Yoko Yokouchi; Donald R. Blake; Kazuyuki Kita; K. Izumi; M. Koike; Y. Komazaki; Y. Miyazaki; M. Fukuda; Y. Kondo, Eighteen C2–C7 NMHCs (nonmethane hydrocarbons) were measured hourly during the Integrated Measurement Program for Aerosol and Oxidant Chemistry in Tokyo (IMPACT) measurement campaigns conducted in central Tokyo during four different periods (summer/autumn of 2003 and winter/summer of 2004). The ambient atmospheric concentrations of NMHCs showed an inverse correlation with wind speed and mixing height and were significantly affected by mesoscale weather conditions. The mixing ratio of isoprene tightly correlated with solar flux and temperature in summer, as it was dominantly emitted by the local vegetation. All the observed NMHCs except isoprene showed high correlation with each other in winter (r 2 > 0.5), suggesting concurrent accumulation under stagnant condition and common sources. Emission ratios were calculated on the basis of the correlation with carbon monoxide and ethyne. Compared to the typical winter NMHC composition, during summer there was a significant increase (up to 7 times higher than wintertime) of C4–C5 alkanes from fuel evaporation; of C2–C3 alkenes, n-hexane and benzene from chemical industry; and of toluene from local manufacturers, reflecting the tempera, AMER GEOPHYSICAL UNION
JOURNAL OF GEOPHYSICAL RESEARCH-Atmosphere, 2007年12月, ［査読有り］

Measurements of reactive nitrogen produced by tropical thunderstorms during BIBLE-C
M. Koike; Y. Kondo; K. Kita; N. Takegawa; N. Nishi; T. Kashihara; S. Kawakami; S. Kudoh; D. Blake; T. Shirai; B. Liley; M. Ko; Y. Miyazaki; Z. Kawasaki; T. Ogawa, The Biomass Burning and Lightning Experiment phase C (BIBLE-C) aircraft mission was carried out near Darwin, Australia ( 12 degrees S, 131 degrees E) in December 2000. This was the first aircraft experiment designed to estimate lightning NO production rates in the tropics, where production is considered to be most intense. During the two flights ( flights 10 and 13 made on December 9 and 11-12, respectively) enhancements of NOx ( NO + NO2) up to 1000 and 1600 parts per trillion by volume (pptv, 10-s data) were observed at altitudes between 11.5 and 14 km. The Geostationary Meteorological Satellite (GMS) cloud ( brightness temperature) data and ground-based lightning measurements by the Global Positioning and Tracking System (GPATS) indicate that there were intensive lightning events over the coast of the Gulf of Carpentaria, which took place upstream from our measurement area 10 to 14 h prior to the measurements. For these two flights, air in which NOx exceeded 100 pptv extended over 620 x 140 and 400 x 170 km(2) ( wind direction x perpendicular direction), respectively, suggesting a significant impact of lightning NO production on NOx levels in the tropics. We estimate the amount of NOx observed between 11.5 and 14 km produced by the thunderstorms to be 3.3 and 1.8 x 10(29) NO molecules for flights 10 and 13, respectively. By using the GPATS lightning flash count data, column NO production rates are estimated to be 1.9-4.4 and 21-49 x 10(25) NO molecules per single flash for these two flight data sets. In these estimations, it is assumed that the column NO production between 0 and 16 km is greater than the observed values between 11.5 and 14 km by a factor of 3.2, which is derived using results reported by Pickering et al. (1998). There are however large uncertainties in the GPATS lightning data in this study and care must be made when the production rates are referred. Uncertainties in these estimates are discussed. The impact on the ozone production rate is also described., AMER GEOPHYSICAL UNION
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 2007年09月, ［査読有り］

Evaluation of ozone column amount from the solar backscattering spectra measured with a spectrograph onboard an aircraft
T. Nakata; K. Kita; M. Suzuki; K. Shiomi; S. Okumura; and T. Ogawa, Slant column amounts of ozone were evaluated from the solar backscattered spectra measured with a simple spectrograph onboard an aircraft over the Pacific Ocean south of Japan in January 2002. A least-squares fitting method optimized on the basis of Bayesian statistics was developed to evaluate them, and the random error in the fitting was about 2.4%. The evaluated slant column amounts of ozone were compared with those calculated from the total ozone data measured with the Total Ozone Mapping Spectrometer (TOMS) on the same day. The differences between the two ranged from a few percent points to more than 20%, and they increased when a small wavelength deviation in the spectrograph occurred due to the aircraft vibration. Excluding the error due to this wavelength deviation, instrumental and systematic errors were estimated to be less than 10%, demonstrating that this airborne measurement with the spectrograph and the developed fitting method could evaluate the ozone column amount with a good accuracy., TERRA SCIENTIFIC PUBL CO
Earth Planets and Space, 2007年08月, ［査読有り］

Partitioning of HNO3 and particulate nitrate over Tokyo: Effect of vertical mixing
Y. Morino; Y. Kondo; N. Takegawa; Y. Miyazaki; K. Kita; Y. Komazaki; M. Fukuda; T. Miyazaki; N. Moteki; and D. R. Worsnop, [ 1] Ground-based measurements of gas-phase nitric acid (HNO3) and particulate nitrate (NO3-) were performed in Tokyo during 2003 - 2004. These measurements provide a comprehensive data set for investigating the diurnal and seasonal variations of gas-phase HNO3 and particulate NO3- and the thermodynamic equilibrium of these compounds. HNO3 and NO3- have distinct diurnal and seasonal variations, especially in summer. This study shows that the thermodynamic equilibrium of HNO3 and NO3- and the production rate of total nitrate (TNO3 = HNO3 + NO3-) are the major controlling factors affecting these seasonal and diurnal variations. A thermodynamic equilibrium model (ISORROPIA) is newly coupled with a one-dimensional (1-D) model to take into account the effect of vertical mixing during daytime on the partitioning of HNO3 and NO3- by constraining the TNO3 concentrations to the observations. The 1-D model reproduces the NO3-/TNO3 ratios observed during daytime, whereas the equilibrium model significantly underestimates these ratios. The agreement between the observed and calculated NO3-/TNO3 ratios is improved over the observed temperature range (1 degrees- 34 degrees C) and relative humidity (18 - 95%) by the 1-D model. These results suggest the importance of vertical mixing in determining HNO3-NO3- partitioning in the boundary layer. It is also found that the mass accommodation coefficient for HNO3 needs to be approximately 0.1 to explain the observed HNO3-NO3- partitioning at the surface., AMER GEOPHYSICAL UNION
J. Geophys. Res., 2006年08月, ［査読有り］

A chemical ionization mass spectrometer for ground-based measurement of nitric acid
K. Kita; Y. Morino; Y. Kondo; Y. Komazaki; N. takegawa; Y. Miyazaki; J. Hirokawa; S. Tanaka; T. L. Thompspn; R.-S. Gao; and D. W. Fahey, 筆頭著者, A chemical ionization mass spectrometer (CIMS) instrument has been developed for high-precision measurements of gaseous nitric acid (HNO3) specifically under high- and variable-humidity conditions in the boundary layer. The instrument's background signals (i.e., signals detected when HNO3-free air is measured), which depend on the humidity and HNO3 concentration of the sample air, are the most important factor affecting the limit of detection (LOD). A new system to provide HNO3-free air without changing both the humidity and the pressure of the sampled air was developed to measure the background level accurately. The detection limit was about 23 parts per trillion by volume (pptv) for 50-s averages. Field tests, including an intercomparison with the diffusion scrubber technique, were carried out at a surface site in Tokyo, Japan, in October 2003 and June 2004. A comparison between the measured concentrations of HNO3 and particulate nitrate indicated that the interference from particulate nitrate was not detectable (i.e., less than about 1%). The intercomparison indicated that the two independent measurements of HNO3 agreed to within the combined uncertainties of these measurements. This result demonstrates that the CIMS instrument developed in this study is capable of measuring HNO3 mixing ratios with the precision, accuracy, and time resolution required for atmospheric science., AMER METEOROLOGICAL SOC
J. Atmos. Ocean Tech., 2006年, ［査読有り］

Combined MU radar and ozonesonde measurements of turbulence and ozone fluxes in the tropo-stratosphere over Shigaraki, Japan
N. M. Gavrilov; S. Fukao; H. Hashiguchi; K. Kita; K. Sato; Y. Tomikawa; and M. Fujiwara, Turbulent diffusivity and turbulent ozone fluxes in the tropo-stratosphere are studied employing simultaneous observations with the Middle and Upper ( MU) Atmosphere radar and ozonesondes in Shigaraki, Japan during April 16 - 24, 1998. A broad region around the tropopause was dynamically active. Maxima of turbulent diffusivity were observed at 8 - 14 km altitude. Such maxima may produce vertical turbulent ozone fluxes across the tropopause with magnitudes comparable to those required for the global ozone budget. Mesometeorological ozone intrusions may enhance the fluxes., AMER GEOPHYSICAL UNION
Geophys. Res. Lett., 2006年, ［査読有り］

航空機搭載センサ"Airborne-OPUS"による二酸化硫黄ガスのリモートセンシング－アルゴリズム開発と検証実験
渡辺征春、奥村真一郎、鈴木 睦、吉田重臣、川上修司、佐野琢己、柴崎和夫、畠山史郎、北 和之、小川利紘, 日本リモートセンシング学会
日本リモートセンシング学会誌, 2006年, ［査読有り］

A springtime comparison of tropospheric ozone and transport pathways on the west coasts of the United States
O. R. Cooper; A. Stohl; S. Eckhardt; D. D. Parrish; S. J. Oltmans; B. J. Johnson; P. Nedelec; F. J. Schmidlin; M. J. Newchurch; Y. Kondo and K. Kita, We have conducted a study to determine the influence of Asian pollution plumes on free tropospheric ozone above the west coast of the United States during spring. We also explored the additional impact of North American emissions on east coast free tropospheric ozone. Long-term ozone monitoring sites in the United States are few, but we obtained ozonesonde profiles from Trinidad Head on the west coast, Huntsville, Alabama, in the southeast, and Wallops Island, Virginia, on the east coast. Additional east coast ozone profiles were measured by the MOZAIC commercial aircraft at Boston, New York City, and Philadelphia. Kilometer-averaged ozone was compared between Trinidad Head and the three east coast sites (MOZAIC, Wallops Island, and Huntsville). Only in the 0-1 km layer did the MOZAIC site have a statistically significant greater amount of ozone than Trinidad Head. Likewise only the 0-1 and 1-2 km layers had greater ozone at Wallops Island and Huntsville in comparison to Trinidad Head. While Wallops Island did show greater ozone than Trinidad Head at 6-9 km, this excess ozone was attributed to a dry air mass sampling bias. A particle dispersion model was used to determine the surface source regions for each case, and the amount of anthropogenic NOx tracer that would have been emitted into each air mass. Transport times were limited to 20 days to focus on the impact of direct transport of pollution plumes from the atmospheric boundary layer. As expected, the amount of NOx tracer emitted into the east coast profiles was much greater in the lower and mid troposphere than at the west coast. At various altitudes at both coasts there existed a significant positive correlation between ozone and the NOx tracer, but the explained variance was generally less than 30%. On the east coast, Wallops Island had the weakest relationship between ozone and the NOx tracer, while Huntsville had the strongest. During spring, differences in photochemistry and transport pathways in the lowest 2 km of the troposphere results in an extra 5-14 ppbv of ozone on the east coast in comparison to Trinidad Head. However, despite differing amounts of NOx tracer from Asia and North America in the free troposphere, we found no significant difference in free tropospheric ozone between the east and west coasts of the United States during spring., AMER GEOPHYSICAL UNION
J. Geophys. Res., 2005年, ［査読有り］

Contribution of particulate nitrate to airborne measurements of total reactive nitrogen
Y. Miyazaki; Y. Kondo; N. Takegawa; R. J. Weber; M. Koike; K. Kita; M. Fukuda; Y. Ma; A. D. Clarke; V. N. Kapustin; F. Flocke; A. J. Weinheimer; M. Zondlo; F. L. Eisele; D. R. Blake; and B. Liley, [1] Simultaneous measurements of speciated, total reactive nitrogen (NOy) and particulate NO3- ( particle diameter < 1.3 mm) were made on board the NASA P-3B aircraft over the western Pacific in February - April 2001 during the Transport and Chemical Evolution over the Pacific (TRACE-P) experiment. Gas-phase and particulate NOy was measured using a gold tube catalytic converter. For the interpretation of particulate NOy, conversion efficiencies of particulate NH4NO3, KNO3, NaNO3, and Ca(NO3)(2) were measured in the laboratory. Only NH4NO3 showed quantitative conversion, and its conversion efficiency was as high as that for HNO3. NOy measured on board the aircraft was found to be systematically higher by 10 - 30% than the sum of the individual NOy gas components (Sigma(NOy)(i)) at 0 - 4 km. Particulate NO3- concentrations measured by a particle-into-liquid sampler (PILS) were nearly equal to NOy - Sigma(NOy)(i) under low-dust-loading conditions. The PILS data showed that the majority of the particulate NO3- was in the form of NH4NO3 under these conditions, suggesting that NH4NO3 particles were quantitatively converted to detectable NO by the NOy converter, consistent with the laboratory experiments. The contribution of particulate NO3- to NOy was most important at 0 - 2 km, where NO3- constituted 10 - 30% of NOy during TRACE-P. On average, the amounts of particulate NO3- and gas-phase HNO3 were comparable in this region., AMER GEOPHYSICAL UNION
J. Geophys. Res., 2005年, ［査読有り］

Estimation of the contribution of intercontinental transport during the PEACE campaign by using a global model
M. Takigawa; K. Sudo; H. Akimoto; K. Kita; N. Takegawa; Y. Kondo; and M. Takahashi, A quasi-real-time calculation system for the global distribution of ozone (O-3) and its precursors, including CO, NOx, and nonmethane hydrocarbons (NMHCs), has been newly developed by using a 3-D chemical-transport model. The model is driven by meteorological data from the National Centers for Environmental Prediction (NCEP), and produces daily 7-day forecast of the distribution of chemical species. The model was used in daily flight planning for the Pacific Exploration of Asian Continental Emission (PEACE)-A and -B aircraft measurement campaigns in January and April-May 2002, respectively. Model-calculated meteorological fields show good agreement with aircraft observations. The model also reproduced events such as polluted air masses in the lower troposphere ( LT) corresponding to post-frontal outflow, a high-concentration CO plume in the upper troposphere (UT) in late spring, and the observed plume that was transported by deep convection over central China. The amount of CO transported into the free troposphere ( FT) by deep convection was estimated to be about 6 Tg CO over China in May 2002. Meridional and seasonal variations in the long-range transport (LRT) of CO tracers, Asian CO tracers, and CO tracers produced from the oxidation of CH4 and NMHCs were all evaluated using tagged CO tracers. LRT CO comprised about 36% of the total CO budget in December-February 2001/2002, and about 20% in March-May 2002 in the free troposphere over Japan. In late spring, the concentration of Asian CO over southern Japan decreased compared to that in winter because the wind direction shifted from northwesterly to easterly or southerly., AMER GEOPHYSICAL UNION
J. Geophys. Res., 2005年, ［査読有り］

Asian chemical outflow to the Pacific in late spring observed during the PEACE-B aircraft mission
N. Oshima; M. Koike; H. Nakamura; Y. Kondo; N. Takegawa; Y. Miyazaki; D. R. Blake; T. Shirai; K. Kita; S. Kawakami; T. Ogawa, The Pacific Exploration of Asian Continental Emission phase B (PEACE-B) aircraft mission was conducted over the western Pacific during April-May 2002. During several flights large enhancements of CO greater than 200 parts per billion by volume (ppbv) were served at altitudes between 5 and 10 km. In this paper, we describe vertical transport mechanisms over east Asia that were responsible for these enhancements, using the European Centre for Medium-Range Weather Forecasts (ECMWF) meteorological data and infrared cloud data obtained by the Geostationary Meteorological Satellite (GMS)-5. A case study for the highest CO event shows that it was likely due to vertical transport of pollutants caused by deep cumulus convection along a quasi-stationary frontal zone, which was formed over central China (around the Yangtze River at 30°N). In the mean meteorological field during the PEACE-B period, the warm, moist low-level southerlies converged into the frontal zone, sustaining cross-frontal temperature and moisture contrasts. Along the frontal zone, the mean vertical motion was distinctively upward, and a subtropical jet aloft was found to transport uplifted air parcels efficiently into the western Pacific. In this study, criteria to identify deep convection are defined using both the ECMWF and GMS data. The results show that convective activity, which was generally high below the subtropical jet, played an important role in producing updrafts over central China. The convective transport resulted mainly from a limited number of episodes, each of which followed the development of a weak cyclonic disturbance. Back trajectories of air parcels sampled at altitudes between 4 and 13 km on board the aircraft during PEACE-B show that among the air parcels originating from the 800-hPa level or below, 69% were likely to have undergone convective uplifting. In addition to convection, sloping isentropes often observed along the quasi-stationary jet axis yielded persistent slow quasi-adiabatic uplifting of air over the Far East, which was occasionally intensified with a classical warm conveyor belt (WCB) airstream on the passage of migratory cyclonic disturbances. Meteorological conditions during PEACE-B were thus favorable for the upliffing of boundary layer air influenced by anthropogenic emissions over central China. These results are consistent with the relatively high levels of Halon 1211 (CF2ClBr), a good tracer of Chinese anthropogenic emissions, observed in the air parcels that were likely uplifted in the frontal zone. Coyright 2004 by the American Geophysical Union.
Journal of Geophysical Research D: Atmospheres, 2004年12月, ［査読有り］

Photochemistry of ozone over the western Pacific from winter to spring
Y.Kondo; N.Nakamura; G.CVhen; N.Takegawa; M.Koike; Y.Miyazaki; K.Kita; J.Crawford; M.Ko; D.R.Blake; S.Kawakami; T.Shirai; B.Liley; Y.Wang; and T.Ogawa, ２００２年に行われたPEACE観測により、アジア大陸から輸送される汚染気塊の影響を受ける西太平洋域でのオゾンの光化学生成の状況を明らかにした（オゾンなどの航空機観測の実行とデータ解釈）。, AMER GEOPHYSICAL UNION
Journal of Geophysical Research,109, 2004年10月, ［査読有り］

Carbonyl sulfide (OCS) and carbon disulfide (CS2): Large scale distributions over the Western Pacific and emissions from Asia during TRACE-P
N. J. Blake; D. G. Streets; J.-H. Woo; I. J. Simpson; J. Green; S. Meinardi; K. Kita; E. Atlas; H. E. Huelberg; G. Sachse; M. A. Avery; S. A. Vay; R. W. Talbot; J. E. Dibb; A. R. Bandy; D. C. Thornton; F. S. Rowland; and D. R. Blake, An extensive set of carbonyl sulfide (OCS) and carbon disulfide (CS2) observations were made as part of the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) project, which took place in the early spring 2001. TRACE-P sampling focused on the western Pacific region but in total included the geographic region 110degreesE to 290degreesE longitude, 5degreesN to 50degreesN latitude, and 0-12 km altitude. Substantial OCS and CS2 enhancements were observed for a great many air masses of Chinese and Japanese origin during TRACE-P. Over the western Pacific, mean mixing ratios of long-lived OCS and shorter-lived CS2 showed a gradual decrease by about 10% and a factor of 5-10, respectively, from the surface to 8-10 km altitude, presumably because land-based sources dominated their distribution during February through April 2001. The highest mean OCS and CS2 levels (580 and 20 pptv, respectively, based on 2.5degrees x 2.5degrees latitude bins) were observed below 2 km near the coast of Asia, at latitudes between 25degreesN and 35degreesN, where urban Asian outflow was strongest. Ratios of OCS versus CO for continental SE Asia were much lower compared to Chinese and Japanese signatures and were strongly associated with biomass burning/biofuel emissions. We present a new inventory of anthropogenic Asian emissions ( including biomass burning) for OCS and CS2 and compare it to emission estimates based on regional relationships of OCS and CS2 to CO and CO2. The OCS and CS2 results for the two methods compare well for continental SE Asia and Japan plus Korea and also for Chinese CS2 emissions. However, it appears that the inventory underestimates Chinese emissions of OCS by about 30-100%. This difference may be related to the fact that we did not include natural sources such as wetland emissions in our inventory, although the contributions from such sources are believed to be at a seasonal low during the study period. Uncertainties in OCS emissions from Chinese coal burning, which are poorly characterized, likely contribute to the discrepancy., AMER GEOPHYSICAL UNION
J. Geophys. Res., 2004年, ［査読有り］

Impacts of Biomass Burning in Southeast Asia on Ozone and Reactive Nitrogen over the Western Pacific in Spring
Y. Kondo; Y. Morino; N. Takegawa; M. Koike; K. Kita; Y. Miyazaki; G. W. Sachse; S. A. Vay; M. A. Avery; F. Flocke; A. J. Weinheimer; F. L. Eisele; M. A. Zondlo; R. J. Weber; H. B. Singh; G. Chen; J. Crawford; D. R. Blake; H. E. Fuelberg; A. D. Clarke; R. W. Talbot; S. T. Sandholm; E.V. Browell; D. G. Streets; and B. Liley, [1] Aircraft measurements of ozone (O-3) and its precursors ( reactive nitrogen, CO, nonmethane hydrocarbons) were made over the western Pacific during the Transport and Chemical Evolution Over the Pacific (TRACE-P) campaign, which was conducted during February - April 2001. Biomass burning activity was high over Southeast Asia ( SEA) during this period ( dry season), and convective activity over SEA frequently transported air from the boundary layer to the free troposphere, followed by eastward transport to the sampling region over the western Pacific south of 30 degreesN. This data set allows for systematic investigations of the chemical and physical processes in the outflow from SEA. Methyl chloride (CH3Cl) and CO are chosen as primary and secondary tracers, respectively, to gauge the degree of the impact of emissions of trace species from biomass burning. Biomass burning is found to be a major source of reactive nitrogen (NOx, PAN, HNO3, and nitrate) and O-3 in this region from correlations of these species with the tracers. Changes in the abundance of reactive nitrogen during upward transport are quantified from the altitude change of the slopes of the correlations of these species with CO. NOx decreased with altitude due to its oxidation to HNO3. On the other hand, PAN was conserved during transport from the lower to the middle troposphere, consistent with its low water solubility and chemical stability at low temperatures. Large losses of HNO3 and nitrate, which are highly water soluble, occurred in the free troposphere, most likely due to wet removal by precipitation. This has been shown to be the major pathway of NOy loss in the middle troposphere. Increases in the mixing ratios of O-3 and its precursors due to biomass burning in SEA are estimated using the tracers. Enhancements of CO and total reactive nitrogen ( NOy), which are directly emitted from biomass burning, were largest at 2 - 4 km. At this altitude the increases in NOy and O-3 were 810 parts per trillion by volume ( pptv) and 26 parts per billion by volume (ppbv) above their background values of 240 pptv and 31 ppbv, respectively. The slope of the O-3-CO correlation in biomass burning plumes was similar to those observed in fire plumes in northern Australia, Africa, and Canada. The O-3 production efficiency ( OPE) derived from the O-3-CO slope and NOx/CO emission ratio ( ER) is shown to be positively correlated with the C2H4/NOx ER, indicating that the C2H4/NOx ER is a critical parameter in determining the OPE. Comparison of the net O-3 flux across the western Pacific region and total O-3 production due to biomass burning in SEA suggests that about 70% of O-3 produced was transported to the western Pacific., AMER GEOPHYSICAL UNION
J. Geophys. Res., 2004年, ［査読有り］

Removal of NOx and NOy in Asian outflow plumes: Aircraft measurements over the western Pacific in January 2002
N. Takegawa; Y. Kondo; M. Koike; G. Chen; T. Machida; T. Watai; D. R. Blake; D. G. Streets; J.-H. Woo; G. R. Carmichael; K. Kita; Y. Miyazaki; T. Shirai; J. B. Liley; and T. Ogawa, [1] The Pacific Exploration of Asian Continental Emission Phase A (PEACE-A) aircraft measurement campaign was conducted over the western Pacific in January 2002. Correlations of carbon monoxide ( CO) with carbon dioxide (CO2) and back trajectories are used to identify plumes strongly affected by Asian continental emissions. DeltaCO/DeltaCO(2) ratios (i.e., linear regression slopes of CO/CO2) in the plumes generally fall within the variability range of the CO/CO2 emission ratios estimated from an emission inventory for east Asia, demonstrating the consistency between the aircraft measurements and the emission characterization. Removal rates of reactive nitrogen (NOx and NOy) for the study region ( altitude < 4 km, 124 degrees - 140 degrees E, 25 degrees - 45 degrees N) are estimated using the correlation with CO2, the photochemical age of the plumes, and the NOx/CO2 emission ratio derived from the emission inventory. The plume age is estimated from the rates of hydrocarbon decay and hydroxyl radical (OH) concentration calculated using a constrained photochemical box model. The average lifetime of NOx is estimated to be 1.2 +/- 0.4 days. Possible processes controlling the NOx lifetime are discussed in conjunction with results from earlier studies. The average lifetime of NOy is estimated to be 1.7 +/- 0.5 days, which is comparable to the NOy lifetime of 1.7 - 1.8 days that has been previously reported for outflow from the United States. This similarity suggests the importance of chemical processing near the source regions in determining the NOy abundance., AMER GEOPHYSICAL UNION
J. Geophys. Res., 2004年, ［査読有り］

Asian chemical outflow to the Pacific in late spring observed during the PEACE-B aircraft mission
N. Oshima; M. Koike; H. Nakamura; Y. Kondo; N. Takegawa; Y. Miyazaki; D. R. Blake; T. Shirai; K. Kita; S. Kawakami; and T. Ogawa, The Pacific Exploration of Asian Continental Emission phase B (PEACE-B) aircraft mission was conducted over the western Pacific during April-May 2002. During several flights, large enhancements of CO greater than 200 parts per billion by volume (ppbv) were observed at altitudes between 5 and 10 km. In this paper, we describe vertical transport mechanisms over east Asia that were responsible for these enhancements, using the European Centre for Medium-Range Weather Forecasts (ECMWF) meteorological data and infrared cloud data obtained by the Geostationary Meteorological Satellite (GMS)-5. A case study for the highest CO event shows that it was likely due to vertical transport of pollutants caused by deep cumulus convection along a quasi-stationary frontal zone, which was formed over central China (around the Yangtze River at 30degreesN). In the mean meteorological field during the PEACE-B period, the warm, moist low-level southerlies converged into the frontal zone, sustaining cross-frontal temperature and moisture contrasts. Along the frontal zone, the mean vertical motion was distinctively upward, and a subtropical jet aloft was found to transport uplifted air parcels efficiently into the western Pacific. In this study, criteria to identify deep convection are defined using both the ECMWF and GMS data. The results show that convective activity, which was generally high below the subtropical jet, played an important role in producing updrafts over central China. The convective transport resulted mainly from a limited number of episodes, each of which followed the development of a weak cyclonic disturbance. Back trajectories of air parcels sampled at altitudes between 4 and 13 km on board the aircraft during PEACE-B show that among the air parcels originating from the 800-hPa level or below, 69% were likely to have undergone convective uplifting. In addition to convection, sloping isentropes often observed along the quasi-stationary jet axis yielded persistent slow quasi-adiabatic uplifting of air over the Far East, which was occasionally intensified with a classical warm conveyor belt (WCB) airstream on the passage of migratory cyclonic disturbances. Meteorological conditions during PEACE-B were thus favorable for the uplifting of boundary layer air influenced by anthropogenic emissions over central China. These results are consistent with the relatively high levels of Halon 1211 (CF2ClBr), a good tracer of Chinese anthropogenic emissions, observed in the air parcels that were likely uplifted in the frontal zone., AMER GEOPHYSICAL UNION
J. Geophys. Res., 2004年, ［査読有り］

Ozone production in transpacific Asian pollution plumes and implications for ozone air quality in California
R. C. Hudman; D. J. Jacob; O. R. Cooper; M. J. Evans; C. L. Heald; R.J. Park; F. Fesenfeld; F. Flocke; J. Holloway; G. Hubler; K. Kita; M. Koike; Y. Kondo; A. Neuman; J. Nowak; S. Oltmans; D. Parrish; J. M. Roberts; and T. Ryerson, We examine the ozone production efficiency in transpacific Asian pollution plumes, and the implications for ozone air quality in California, by using aircraft and surface observations in April-May 2002 from the Intercontinental Transport and Chemical Transformation 2002 (ITCT 2K2) campaign off the California coast and the Pacific Exploration of Asian Continental Emission-B (PEACE-B) campaign over the northwest Pacific. The observations are interpreted with a global three-dimensional chemical transport model (GEOS-CHEM). The model reproduces the mean features observed for CO, reactive nitrogen oxides (NOy), and ozone but underestimates the strong (similar to20 ppbv) stratospheric contribution to ozone in the middle troposphere. The ITCT 2K2 aircraft sampled two major transpacific Asian pollution plumes, one on 5 May at 5-8 km altitude with CO up to 275 ppbv but no elevated ozone and one on 17 May at 2.5-4 km altitude with CO up to 225 ppbv and ozone up to 90 ppbv. We show that the elevated ozone in the latter plume is consistent with production from peroxyacetylnitrate (PAN) decomposition during subsidence of the plume over the northeast Pacific. This production is particularly efficient because of the strong radiation and low humidity of the subsiding environment. We argue that such PAN decomposition represents a major and possibly dominant component of the ozone enhancement in transpacific Asian pollution plumes. Strong dilution of Asian pollution plumes takes place during entrainment in the U. S. boundary layer, greatly reducing their impact at U. S. surface sites. California mountain sites are more sensitive to Asian pollution because of their exposure to the free troposphere. Model results indicate a mean Asian pollution enhancement of 7 ppbv ozone at Sequoia National Park in May 2002 on those days when the 8-hour average ozone concentration exceeded 80 ppbv., AMER GEOPHYSICAL UNION
J. Geophys. Res., 2004年, ［査読有り］

奥日光山岳域における夏季および秋季のオゾン濃度変動
畠山史郎,北 和之, 近年関東周辺山岳域で見られる森林衰退の原因として大気汚染物質の影響が重要ではないかといわれている。しかし, この地域でのこれまでの観測は電源の都合により, 長期的な観測が出来ず, そのため観測時の天候に大きく影響されて, 大気汚染の影響が十分把握されていない。本研究では電源に太陽電池を用いることにより, 実際に森林被害の激しい前白根山山頂付近で, 大気汚染物質であるオゾン (0₃) を, 約3ヵ月にわたって長期的に観測することで, この地域での0₃濃度変化を明らかにした。更に高濃度0₃が現れる頻度やその起源, それらが出現する気象条件を考察した。その結果, 今回の観測では, 期間中の最高濃度は1時間平均値で70ppb弱であり, 過去に観測された100ppbを超えるような高濃度は観測されなかった。また, 長期間の統計的な03濃度変化を調べることにより, この地点で0₃が高濃度になるのは夏季の卓越した南風に加えて, 日射強度が大きい時であることが分かった。これは強い日射により, 都市域で発生した一次汚染物質が光化学反応を起こしながら, 広域な海陸風循環によって輸送されてきた為であると考えられた。また, 9月以降の秋季には0₃の平均濃度が上がると共に日変化が小さくなった。これは山頂付近では自由対流圏大気の影響が大きくなり, アジアのバックグラウンドオゾンが輸送されていて, 関東平野部からの汚染空気の寄与が小さくなるためと考えられた。, Japan Society for Atmospheric Environment
大気環境学会誌, 2004年

Removal of NOx and NOy in biomass burning plumes in the boundary layer over northern Australia
N. Takegawa; Y. Kondo; M. Koike; M. Ko; K. Kita; D. R. Blake; N. Nishi; W. Hu; J. B. Liley; S. Kawakami; T. Shirai; Y. Miyazaki; H. Ikeda; J. Russell-Smith; and T. Ogawa, [1] The Biomass Burning and Lightning Experiment Phase B (BIBLE-B) aircraft measurement campaign was conducted over the western Pacific and Australia in August and September 1999. In situ aircraft measurements of carbon monoxide (CO), nitric oxide (NO), total reactive nitrogen (NOy), ozone (O-3), nonmethane hydrocarbons (NMHCs), and other species were made during BIBLE-B. Meteorological analysis shows that the trace gases emitted from biomass burning in northern Australia were mostly confined within the planetary boundary layer (below 3 km) by strong subsidence in the free troposphere. Removal processes of NOx (equal to measured NO + calculated NO2) and NOy in biomass burning plumes in the boundary layer are examined on the basis of correlation analysis. The photochemical lifetime of NOx in biomass burning plumes during the daytime is estimated to be 0.1 to 0. 3 days using the correlations of NOx with short-lived NMHCs and hydroxyl radical (OH) concentration calculated from a constrained photochemical model. Correlation of NOy with CO shows that 60% of the NOy molecules originating from biomass burning were removed in the boundary layer within 2-3 days. This result is consistent with dry deposition of nitric acid (HNO3)in the plumes. It is likely that only a small fraction of NOy emitted from biomass burning was exported from the boundary layer to the free troposphere during the BIBLE-B period., AMER GEOPHYSICAL UNION
J. Geophys. Res., 2003年05月, ［査読有り］

Springtime photochemical ozone production observed in the upper troposphere over East Asia　　　　　　　　　　　　　　　
Y. Miyazaki; K. Kita; Y. Kondo; M. Koike; M. Ko; W. Hu; S. Kawakami; D. R. Blake; T. Ogawa
J. Geophys. Res., 2003年, ［査読有り］

Photochemical production of ozone in the upper troposphere in association with cumulus convection over Indonesia　　　　　　　　　　　　　　　
K. Kita; S. Kawakami; Y. Miyazaki; Y. Higashi; Y. Kondo; N. Nishi; M. Koike; D. R. Blake; T. Machida; T. Sano; W. Hu; M. Ko; T. Ogawa, 筆頭著者
J. Geophys. Res., 2003年, ［査読有り］

Photochemical ozone budget during BIBLE-A and B campaigns　　　　　　　　　　　　　　　
M. Ko; W. Hu; J. Rodriguez; Y. Kondo; M. Koike; K. Kita; S. Kawakami; D. Blake; S. Liu
J. Geophys. Res., 2003年, ［査読有り］

Effects of biomass burning, lightning, and convection on O3, CO, and NOy over the tropical Pacific and Australia in August-October　　　　　　　　　　　　　　　
Y. Kondo; M. Koike; K. Kita; H. Ikeda; N. Takegawa; I. Bey; D.J. Jacob; S. Kawakami; D. Blake; S.C. Liu; M. Ko; H. Irie; Y. Miyazaki; Y. Higashi; B. Liley; N. Nishi; Y. Zhao; T. Ogawa
J. Geophys. Res., 2003年, ［査読有り］

Black carbon in aerosol during BIBLE-B　　　　　　　　　　　　　　　
J. B. Liley; D. Baumgardner; Y. Kondo; K. Kita; D. R. Blake; M. Koike; T. Machida; N. Takegawa; S. Kawakami; T. Shirai; T. Ogawa
J. Geophys. Res., 2003年, ［査読有り］

Vertical and meridional distributions of the atmospheric CO2 mixing ratio between northern mid latitudes and southern subtropics
T. Machida; K. Kita; Y. Kondo; D. Blake; S. Kawakami; G. Inoue; T. Ogawa
J. Geophys. Res., 2003年, ［査読有り］

Emission estimates of selected volatile organic compounds from tropical savanna burning in northern Australia
T. Shirai; D. R. Blake; S. Meinardi; F. S. Rowland; J. Russel-Smith; A. Edwards; Y. Kondo; M. Koike; K. Kita; T. Machida; N. Takegawa; N. Nishi; S. Kawakami; and T. Ogawa, [1] Here we present measurements of a range of carbon-based compounds: carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), nonmethane hydrocarbons (NMHCs), methyl halides, and dimethyl sulfide (DMS) emitted by Australian savanna fires studied as part of the Biomass Burning and Lightning Experiment (BIBLE) phase B aircraft campaign, which took place during the local late dry season (28 August to 13 September 1999). Significant enhancements of short-lived NMHCs were observed in the boundary layer (BL) over the region of intensive fires and indicate recent emissions for which the mean transport time was estimated to be about 9 hours. Emission ratios relative to CO were determined for 20 NMHCs, 3 methyl halides, DMS, and CH4 based on the BL enhancements in the source region. Tight correlations with CO were obtained for most of those compounds, indicating the homogeneity of the local savanna source. The emission ratios were in good agreement with some previous measurements of savanna fires for stable compounds but indicated the decay of emission ratios during transport for several reactive compounds. Based on the observed emission ratios, emission factors were derived and compared to previous studies. While emission factors (g species/kg dry mole) of CO2 varied little according to the vegetation types, those of CO and NMHCs varied significantly. Higher combustion efficiency and a lower emission factor for methane in this study, compared to forest fires, agreed well with results for savanna fires in other tropical regions. The amount of biomass burned was estimated by modeling methods using available satellite data, and showed that 1999 was an above average year for savanna burning. The gross emissions of the trace gases from Australian savanna fires were estimated., AMER GEOPHYSICAL UNION
J. Geophys. Res., 2003年, ［査読有り］

Ozonesonde observations in the Indonesian maritime continent: A case study on ozone rich layer in the equatorial upper troposphere
M. Fujiwara; Y. Tomikawa; K. Kita; Y. Kondo; N. Komala; S. Saraspriya; T. Manik; A. Suripto; S. kawakami; T. Ogawa; E. kelena; B. Suhardi; S. W. B. Harijono; M. Kudsy; T. Sribimawati; M. D. Yamanaka, Ozonesonde observation campaigns were conducted over the Indonesian maritime continent in September-October 1998 and in August-September 1999. Three stations were used for each campaign, Watukosek (7.5degreesS, 112.6degreesE), Kototabang (0.20degreesS, 100.3degreesE), and Pontianak (0.03degreesN, 109.3degreesE) for the 1998 campaign, and Watukosek, Kototabang, and Darwin (12.25degreesS, 130.55degreesE) for the 1999 campaign. Both periods were basically characterized as the La Nina period, and the tropospheric ozone concentrations showed normal values. Temporal variation and horizontal distribution of an ozone layered structure with a 1-1.5-km thickness were obtained just below the tropopause at the two equatorial stations during the 1998 campaign. Meteorological data analyses including the reverse domain filling technique suggested that the most plausible explanation for the layer is the quasi-horizontal, thin intrusion from the northern midlatitude lower stratosphere associated with a breaking Rossby wave and large-scale flow pattern. (C) 2002 Elsevier Science Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
Atmos. Environ., 2003年, ［査読有り］

Photochemical production of O3 in biomass burning plumes in the boundary layer over northern Australia
N. Takegawa; Y. Kondo; M. Ko; M. Koike; K. Kita; D. R. Blake; W. Hu; C. Scott; S. Kawakami; Y. Miyazaki; J. Russel-Smith; and T. Ogawa, [1] In situ aircraft measurements of ozone (O-3) and its precursors were made over northern Australia in August September 1999 during the Biomass Burning and Lightning Experiment Phase B (BIBLE-B). A clear positive correlation of O3 with carbon monoxide ( CO) was found in biomass burning plumes in the boundary layer (<3 km). The Delta O-3/Delta CO ratio ( linear regression slope of O-3-CO correlation) is found to be 0.12 ppbv/ppbv, which is comparable to the ratio of 0.15 ppbv/ppbv observed at 0 4 km over the Amazon and Africa in previous studies. The net flux of O-3 exported from northern Australia during BIBLE-B is estimated to be 0.3 Gmol O-3/day. In the biomass burning region, large enhancements of O-3 were coincident with the locations of biomass burning hot spots, suggesting that major O-3 production occurred near fires ( horizontal scale < 50 km)., AMER GEOPHYSICAL UNION
J. Geophys. Res. Lett., 2003年, ［査読有り］

Synoptic-scale transport of reactive nitrogen over the western Pacific in spring
Y. Miyazaki; Y. Kondo; M. Koike; H. E. Fuelberg; C. M. Kiley; K. Kita; N. Takegawa; G. W. Sachse; F. Flocke; A. J. Weinheimer; H. B. Singh; F. J. Eisele; M. Zondlo; R. W. Talbot; S. T. Sandholm; M. A. Avery; and D. R. Blake, [1] Pathways of synoptic-scale uplifted transport of pollutants from East Asia and their effects on chemical distributions of NOy species are investigated based on a subset of the aircraft data obtained during the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) experiment, conducted in February-April 2001. Meteorological and chemical analyses indicate that 73% of the uplifted transport was associated with warm conveyor belts (WCBs) and convective outflow (COF), which transported air masses strongly impacted by biomass burning over Southeast Asia. The rest (27%) of the uplifted air masses originated over coastal regions of northeast China, where fossil fuel combustion was a dominant source of pollutants. Both WCB associated with a midlatitude cyclone and COF associated with a stationary front over southeast China are examined in detail for the April 4 case. During the TRACE-P period, low NOx(= NO + NO2)/ NOy ratios in the WCB and COF indicate that a significant part of the NOx was oxidized to nitric acid (HNO3) and peroxyacetyl nitrate (PAN) during transport. Low HNO3/NOy ratios in the WCB and COF airstreams indicate that a large amount of HNO3 was removed during transport on timescales within 1-3 days. PAN was found to be the dominant form of NOy in air masses transported by the WCB and COF, likely due to the production of PAN in regions of biomass burning and industrial emissions, as well as due to the rapid removal of HNO3 during transport. For emissions that were transported to the free troposphere by WCBs and COF, about 10-20% of the NOy remained after transport to the free troposphere, and 30% of the NOy surviving in the boundary layer in limited cases. The results indicate that the WCB and COF provide both an efficient sink for HNO(3 a)nd an efficient mechanism for the transport of PAN from the boundary layer to the free troposphere over the western Pacific., AMER GEOPHYSICAL UNION
J. Geophys. Res., 2003年, ［査読有り］

Export of anthropogenic reactive nitrogen and sulfur compounds from the East Asia region in spring
M. Koike; Y. Kondo; K. Kita; N. Takegawa; Y. Masui; Y. Miyazaki; M. W. Ko; A. J. Weinheimer; F. Flocke; R. J. Weber; D. C. Thornton; G. W. Sachse; S. A. Vay; D. R. Blake; D. G. Streets; F. L. Eisele; S. T. Sandholm; H. B. Singh; R. W. Talbot, Measurements of gaseous and particulate reactive nitrogen and sulfur species, as well as other chemical species, were made using the P-3B and DC-8 aircraft over the western Pacific during the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) experiment, conducted between February and April 2001. These measurements provide a good opportunity to study the extent to which anthropogenic NOx and SO2 emitted over the East Asian countries remain as NOy and SOx (=SO2 + nssSO(4)(2-)) in the form of gas or fine particles when an air mass is transported into the western Pacific region. In this paper a method to estimate transport efficiencies, epsilon(NOy) and epsilon(SOx), in an air mass that has experienced multiple injection, mixing, and loss processes is described. In this analysis, CO and CO2 are used as passive tracers of transport, and the emission inventories of CO, CO2, NOx, and SO2 over the East Asia region are used. Results from the P-3B presented in this study indicate that 20-40% and 15% of NOx emitted over the northeastern part of China remained as NOy over the western Pacific in the boundary layer (BL) and free troposphere (FT), respectively. In the FT, PAN is found to have been the dominant form of NOy, while only 0.5% of emitted NOx remained as NOx. The transport efficiency of SOx is estimated to have been 25-45% and 15-20% in the BL and FT, respectively. Median values of the nssSO(4)(2-)/SOx ratio are 0.4-0.6 both in the BL and FT, however large variability is found in the FT. These results are generally consistent with those derived using DC-8 data. The results obtained in this study indicate that more than half of NOy and SOx were lost over the continent and that the vertical transport from the BL to FT further reduced their amounts by a factor of 2, likely due to wet removal. Budgets of NOy and SOx were also studied for air masses, which we sampled during TRACE-P and the flux out from the continent in these cases is estimated to be 20% of the emissions. Flux in the BL and FT is found to have a similar contribution., AMER GEOPHYSICAL UNION
J. Geophys. Res., 2003年, ［査読有り］

NMHCs and halocarbons in Asian continental outflow during Transport and Chemical Evolution over the Pacific (TRACE-P): Comparison with PEM WEST-B
N. J. Blake; D. R. Blake; I. J. Simpsons; S. Meinardi; A. L. Swanson; J. P. Lopez; A. S. Katzenstein; B. Barletta; T. Shirai; E. Atlas; G. Sachse; M. Avery; S. Vay; H. E. Fuelberg; C. M. Kiley; K. Kita; F. S. Rowland, [1] We present an overview of the spatial distributions of nonmethane hydrocarbons ( NMHCs) and halocarbons observed over the western north Pacific as part of the NASA GTE Transport and Chemical Evolution over the Pacific (TRACE-P) airborne field campaign ( February-April 2001). The TRACE-P data are compared with earlier measurements from the Pacific Rim during the Pacific Exploratory Mission-West B ( PEM-West B), which took place in February-March 1994, and with emission inventory data for 2000. Despite the limited spatial and temporal data coverage inherent to airborne sampling, mean levels of the longer-lived NMHCs ( including ethane, ethyne, and benzene) were remarkably similar to our results during the PEM-West B campaign. By comparison, mixing ratios of the fire extinguisher Halon-1211 (CF2ClBr) increased by about 50% in the period between 1994 and 2001. Southern China ( south of 35degreesN), and particularly the Shanghai region, appears to have been a substantial source of Halon-1211 during TRACE-P. Our previous analysis of the PEM-West B data employed methyl chloroform ( CH3CCl3) as a useful industrial tracer. However, regulations have reduced its emissions to the extent that its mixing ratio during TRACE-P was only one-third of that measured in 1994. Methyl chloroform mixing ratio "hot spots,'' indicating regions downwind of continuing emissions, included outflow from the vicinity of Shanghai, China, but particularly high emission ratios relative to CO were observed close to Japan and Korea. Tetrachloroethene ( C2Cl4) levels have also decreased significantly, especially north of 25degreesN, but this gas still remains a useful indicator of northern industrial emissions. Methyl bromide ( CH3Br) levels were systematically 1-2 pptv lower from 1994 to 2001, in accord with recent reports. However, air masses that had been advected over Japan and/or South Korean port cities typically exhibited elevated levels of CH3Br. As a consequence, emissions of CH3Br from Japan and Korea calculated employing CH3Br/CO ratios and scaled to CO emission inventory estimates, were almost as large as for all of south China ( south of 35degreesN). Total east Asian emissions of CH3Br and CH3Cl were estimated to be roughly 4.7 Gg/yr and 167 Gg/yr, respectively, in 2001., AMER GEOPHYSICAL UNION
J. Geophys. Res., 2003年, ［査読有り］

Measurement of NO2 by the photolysis conversion technique during the Transport and Chemical Evolution Over the Pacific (TRACE-P) campaign
K. Nakamura; Y. Kondo; G. Chen; J. H. Crawford; N. Takegawa; M. Koike; K. Kita; Y. Miyazaki; R. E. Shetter; B. L. Lefer; M. Avery; J. Matsumoto, An airborne instrument for in situ measurements of tropospheric nitrogen dioxide (NO2) was developed using the photolytic conversion technique followed by chemiluminescence detection of NO. This instrument was used for the measurements of NO2 on board the NASA P-3B aircraft during the Transport and Chemical Evolution Over the Pacific (TRACE-P) campaign. Comparison in the laboratory indicated less than 10% difference between our NO2 instrument and two independent laser-induced fluorescence instruments in the NO2 range of 30 parts per trillion by volume (pptv) to 50 ppbv. The magnitudes of potential errors in airborne tropospheric NO2 measurements were further assessed using the TRACE-P data set. The systematic errors estimated for the median NO2 mixing ratios, 70 pptv at 0-2 km (30 pptv at 2-8 km), were 19% (39%). The random errors for a 10 s integration time were estimated to be 5-10%, depending on altitude. The observed NO2 mixing ratios were compared to those calculated by a photochemical box model. Overall, the calculated NO2 values correlated very well with those observed (r(2)=0.97), although the calculations were systematically higher than the observations by about 30%, except for the highest flight levels. The calculated/observed NO2 ratio remained nearly constant, having values close to 1.3 at 0-4 km, and decreased with altitude. The difference between the observed and model-calculated values, however, was within the combined uncertainty in the measurement and model calculation. The underlying causes for this difference are to be determined in future studies., AMER GEOPHYSICAL UNION
J. Geophys. Res., 2003年, ［査読有り］

Effects of biomass burning and lightening on atmospheric chemistry over Austraria and South-east Asia
Y.KOndo; N.Takegawa; Y.Miyazaki; M.Ko; M.Koike; K.Kita; S.Kawakami; T.Shirai; T.Ogawa; D.R.Blake; B.Liley; and J.Russel-Smith, 1998~2000年に東南アジア～北部オーストラリアで行った航空機観測により、これらの地域でのバイオマス燃焼や雷活動が、対流圏オゾンに与える影響を明らかにした（航空機観測計画の立案に参加、オゾン・一酸化炭素などの航空機観測及び観測データの提供とデータ解析）。, CSIRO PUBLISHING
International Journal of Wildland Fire, 2003年

Effects of biomass burning, lightning, and convection on O3, CO, and NOy over the tropical Pacific and Australia in August-October 1998 and 1999
Kondo, Y; M. Koike; K. Kita; H. Ikeda; N. Takegawa; S. Kawakami; D. Blake; S.C. Liu; M. Ko; Y. Miyazaki; H. Irie; Y. Higashi; B. Liley; N. Nishi; Y. Zhao; T. Ogawa, In situ aircraft measurements of O-3, CO, total reactive nitrogen (NOy), NO, and non-methane hydrocarbons (NMHCs) were made over the western Pacific Ocean and Australia during the Biomass Burning and Lightning Experiment (BIBLE) A and B conducted in August-October 1998 and 1999. Generally, similar features were seen in the BIBLE A and B data in the latitudinal variations of these species in the troposphere from 35degreesN to 28degreesS at longitudes of 120degrees-150degreesE. The focus of this paper is to describe the characteristics of air masses sampled at 15degreesN-10degreesS (tropical Pacific) and 10degreesS-28degreesS (over Australia). With the exception of occasional enhancements in reactive nitrogen seen over New Guinea associated with lightning activities, the tropical Pacific region is distinguished from the rest of the region by smaller concentrations of these trace species. This can be explained in terms of the absence of surface sources over the ocean, lack of stratospheric intrusion, and the preclusion of midlatitude air and air from the west due to active convection throughout the troposphere. The median O-3, CO, NOy, and NO mixing ratios in tropical air above 4 km were about 15-20 parts per billion by volume (ppbv), 60-75 ppbv, 20-100 parts per trillion by volume (pptv), and 5-40 pptv, respectively. Data obtained from PEM-West A and B conducted in 1991 and 1994 showed similar latitudinal features, although the PEM-West A values were somewhat elevated due to dominating westerly winds in the lower troposphere associated with El Nino. Over Australia, the levels of O-3, CO, NOy, NO, and NMHCs were elevated throughout the troposphere over those observed in the tropical Pacific both in 1998 and 1999. The effect from biomass burning that occurred in northern Australia was limited to within the boundary layer because of strong subsidence in the period. Analyses based on 14-day back trajectories identified free tropospheric air over Australia that originated from Indonesia, the Indian Ocean, Africa, and southern midlatitudes. The levels of O-3, CO, NOy, and NMHCs in these air masses were much higher than those from the tropical Pacific due to their stronger sources from biomass burning and lightning. These values are compared with those obtained in the South Pacific during PEM-Tropics A. Effects of biomass burning and lightning are discussed as possible sources of O-3 and its precursors in these air masses., AMER GEOPHYSICAL UNION
Journal of Geophysical Research Atmospheres, 2002年12月, ［査読有り］

Reactive nitrogen over the tropical Western Pacific: Influence from lightning and biomass burning during BIBLE A
M. Koike; Y. Kondo; D. Akutagawa; K. Kita; N. Nishi; S.C. Liu; D. Blake; S. Kawakami; N. Takegawa; M. Ko; Y. Zhao; T. Ogawa
Journal of Geophysical Research Atmospheres, 2002年02月, ［査読有り］

Formation of an ozone lamina due to differential advection revealed by intensive observations
Y. Tomikawa; K. Sato; K. Kita; M. Fujiwara; M. Yamamori and T. Sano, [1] An intensive observation with ozonesondes, radiosondes, and the Middle and Upper atmosphere (MU) radar was conducted at Shigaraki (34.9degreesN, 136.1degreesE), Japan, from 16 through 24 April 1998 to investigate the formation mechanism of ozone laminae in the midlatitude lower stratosphere. In these observations the temporal variation of an ozone lamina at Shigaraki was continuously observed through a short time interval of 8 hours. During the observation period an ozone lamina with a thickness of 2-3 km appeared and ascended with a speed of similar to1 km day(-1) in the height region of 18-21 km. It is deduced that inertia gravity waves existing in this height region did not contribute to formation of the ozone lamina, because their amplitudes were too small and their vertical phase propagation was in the opposite direction. The reverse domain filling method was used to reconstruct the "high-resolution'' modified potential vorticity field using backward trajectory calculations. The results indicate that this ozone lamina was caused by differential advection due to the vertical shear associated with the subtropical westerly jet and embedded stationary Rossby wave therein. This means that large-scale motions concurrent with vertical wind shear can produce much smaller-scale structures in material fields than those of the large-scale motions themselves., AMER GEOPHYSICAL UNION
J. Geophys. Res., 2002年, ［査読有り］

Airborne vacuum ultraviolet resonance fluorescence instrument for in situ measurement of CO
N. Takegawa; K. Kita; Y. Kondo; Y. Matsumi; D. D. Parrish; J. S. Holloway; M. Koike; Y. Miyazaki; N. Toriyama; S. Kawakami; and T. Ogawa, An airborne instrument for fast-response, high-precision measurement of tropospheric carbon monoxide (CO) was developed using a vacuum ultraviolet (VUV) resonance fluorescence technique. The excitation radiation is obtained by a DC discharge CO resonance lamp combined with an optical filter for the CO fourth positive band emission around 150 run. The optical filter consists of a VUV monochromator and a crystalline quartz window (< 147-nm cutoff). The crystalline quartz window ensures a sharp: discrimination against wavelengths below 135.7 nm that yield a positive interference from water vapor. Laboratory tests showed that the optical system achieved a precision of 1.1 parts per billion by volume (ppbv) at a CO concentration of 100 ppbv for a 1-s integration period, and the flow system provided a response time (Ile time constant) of similar to2 s. The aircraft measurement campaign Biomass Burning and Lightning Experiment-phase B (BIBLE-B) was conducted between August and September 1999 over the western Pacific and Australia. The flight data obtained during this campaign were used to demonstrate the high precision and fast response of the instrument. An intercomparison of the VUV CO measurement and a gas chromatographic CO measurement was conducted during BIBLE-B. Overall, these two independent measurements showed good agreement, within the experimental uncertainties., AMER GEOPHYSICAL UNION
J. Geophys. Res., 2001年, ［査読有り］

Seasonal variation of tropospheric ozone in Indonesia revealed by 5-year ground-based observations
M. Fujiwara; K. Kita; T. Ogawa; S. Kawakami; T. Sano; N. Komala; S. Saraspriya and A. Suriputo, Regular ozonesonde observation and total ozone observation with the Brewer spectrophotometer have been conducted at Watukosek (7.5°S, 112.6°E), Indonesia, since 1993. Three seasons are recognized for the vertical distribution of tropospheric ozone. (1) During the local wet season, between December and March, the ozone mixing ratio is nearly constant at 25 ppbv throughout the troposphere. (2) During the transition season from wet to dry, between April and July, the mixing ratio is often enhanced in the uppermost troposphere. (3) During the local dry season, between August and November, the concentration is enhanced in the planetary boundary layer, and extensive forest fires in Indonesia associated with the strong El Niño events of 1994 and of 1997 have enhanced the ozone mixing ratio in the middle troposphere, the integrated tropospheric ozone, and the total ozone at Watukosek. Copyright 2000 by the American Geophysical Union., Blackwell Publishing Ltd
J. Geophys. Res., 2000年, ［査読有り］

Seasonal variation of tropospheric ozone in Indonesia revealed by 5-year ground-based observations
M Fujiwara; K Kita; T Ogawa; S Kawakami; T Sano; N Komala; S Saraspriya; A Suripto, Regular ozonesonde observation and total ozone observation with the Brewer spectrophotometer have been conducted at Watukosek (7.5 degrees S, 112.6 degrees E), Indonesia, since 1993. Three seasons are recognized for the vertical distribution of tropospheric ozone. (1) During the local wet season, between December and March, the ozone mixing ratio is nearly constant at 25 ppbv throughout the troposphere. (2) During the transition season from wet to dry, between April and July, the mixing ratio is often enhanced in the uppermost troposphere. (3) During the local dry season, between August and November, the concentration is enhanced in the planetary boundary layer, and extensive forest fires in Indonesia associated with the strong El Nino events of 1994 and of 1997 have enhanced the ozone mixing ratio in the middle troposphere, the integrated tropospheric ozone, and the total ozone at Watukosek., AMER GEOPHYSICAL UNION
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 2000年01月, ［査読有り］

Impact of aircraft emissions on reactive nitrogen over the North Atlantic Flight Corridor region
M. Koike; Y. Kondo; H. Ikeda; G.L. Gregory; B.E. Anderson; G.W. Sachse; D. Blake; S.C. Liu; H.B. Singh. A. Thompson; K. Kita; Y. Zhao; T. Sugita; R.E. Shetter; and N. Toriyama, The impact of aircraft emissions on reactive nitrogen in the upper troposphere (UT) and lowermost stratosphere (LS) was estimated using the NOy-O-3 correlation obtained during the Subsonic Assessment (SASS) Ozone and Nitrogen Oxide Experiment (SONEX) carried out over the U.S. continent and North Atlantic Flight Corridor (NAFC) region in October and November 1997. To evaluate the large-scale impact, we made a reference NOy-O-3 relationship in air masses, upon which aircraft emissions were considered to have little impact. For this purpose, the integrated input of NO, from aircraft into an air mass along a 10-day back trajectory (Delta NOy) was calculated based on the Abatement of Nuisance Caused by Air Traffic/European Commission (ANCAT/EC2) emission inventory. The excess NOy (dNO(y)) was calculated from the observed NO, and the reference NOy-O-3 relationship. As a result, a weak positive correlation was found between the dNO(y) and Delta NOy and dNO(y) and NOx/NOy values, while no positive correlation between the dNO(y) and CO values was found suggesting that dNO(y) values can be used as a measure of the NOx input from aircraft emissions. The excess NOy values calculated from another NOy-O-3 reference relationship made using in situ condensation nuclei data also agreed with these dNO(y) values, within the uncertainties. At the NAFC region (45 degrees N-60 degrees N) the median value of dNO(y) in the troposphere increased with altitude above 9 km and reached 70 parts per trillion by volume (pptv) (20% of NOy) at 11 km. The excess NOx was estimated to be about half of the dNO(y) values, corresponding to 30% of the observed NOx level. Higher dNO(y), values were generally found in air masses where O-3 = 75-125 ppbv, suggesting a more pronounced effect around the tropopause. The median value of dNO(y) in the stratosphere at the NAFC region at 8.5-11.5 km was about 120 pptv. The higher dNO(y) values in the LS were probably due to the accumulated effect of aircraft emissions, given the long residence time of affected air in the LS. Similar dNO(y) values were also obtained in air masses sampled over the U.S. continent., AMER GEOPHYSICAL UNION
J. Geophys. Res., 2000年, ［査読有り］

Total ozone increase associated with forest fires over the Indonesian region and its relation to the El Nino-Southern Oscillation
K. Kita; M. Fujiwara and S. Kawakami, 筆頭著者, Significant increases of total ozone were observed both by the total ozone mapping spectrometer (TOMS) and by the Brewer spectrophotometer in Indonesia in September and October of 1994 and 1997, during the El Nino periods, when extensive forest fires were reported in Sumatra Island, Kalimantan (the southern part of Borneo Island) and south New Guinea. The two observations were consistent with each other, and the total ozone increases were attributed to the tropospheric ozone increases because their amplitudes agreed with those of integrated tropospheric ozone increases derived from ozonesonde observations. The TOMS data indicated that the horizontal distributions and temporal variations of the ozone increases were similar in both years; the ozone increases were found mainly over Sumatra Island and the Malay Peninsula in September, and spread out from Kalimantan to the central Indian Ocean in October. This ozone distribution was partly different from the reported fire areas. This difference suggested the importance of the horizontal advection due to the easterly wind in the lower troposphere and of the vertical transport due to the upward wind at the west of Sumatra Island, in the ozone maximum area. Distinctive total ozone increases similar to those in 1994 and 1997 repeatedly appeared over the Indonesian region in the TOMS data between 1979 and 1998. The average ozone increase in this region was estimated by subtracting the background structure of total ozone in the tropics, and this analysis showed that large ozone increases mostly occurred in the dry season during the El Nino periods when the precipitation decreased significantly and extensive forest fires occurred frequently in Indonesia. (C) 2000 Elsevier Science Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
Atmos. Environ., 2000年, ［査読有り］

Increase of ozone and ozone precursor gases in the upper troposphere over the Indonesian-Northern Australian region observed during BIBLE-A aircraft observation campaign　　　　　　　　　　　　　　　
K. Kita; Y. Miyazaki; Y. Higashi; S. Kawakami; T. Sano; M. Takeda; N. Nishi; Y. Kondo; M. Koike; D. R. Blake; N. Blake; B. Liley; T. Machida; W. Hu; M. Ko; J. Rodriguez; T. Ogawa
Proceedings of Quadrennial Ozone Symposium Sapporo 2000, 2000年

Ozone-increased layers in the free troposphere observed over Indonesia and Northern Australia in BIBLE-A and B aircraft observation campaigns　　　　　　　　　　　　　　　
Y. Higashi; K. Kita; Y. Miyazaki; Y. Tomikawa; M. Fujiwara; S. Kawakami; T. Shirai; N. Nishi; Y. Kondo; D. Blake; B. Liley; N. Komala; S. Saraspriya; A. Suripto; M. Timbul; T. Ogawa
Proceedings of the Quadrennial ozone symposium Sapporo 2000, 2000年

Observation and origin of dry sir with high mixing ratios of ozone and its precursor gases in the tropical and subtropical upper troposphere during BIBLE aircraft observations　　　　　　　　　　　　　　　
S. Kawakami; K. Kita; Y. Miyazaki; Y. Higashi; M. Fujiwara; Y. Tomikawa; N. Nishi; Y. Kondo; D. Blake; B. Liley; N. Komala; S. Saraspriya; A. Suripto; A. Shirai; T. Ogawa, Proceedings of Quadrennial Ozone Symposium Sapporo 2000
Proceedings of Quadrennial Ozone Symposium Sapporo 2000, 2000年

Photochemical ozone budget during BIBLE-A campaign　　　　　　　　　　　　　　　
M. Ko; J. Rodriguez; W. HU; Y. Kondo; M. Koike; K. Kita; S. Kawakami; D. Blake
Proceedings of Quadrennial Ozone Symposium Sapporo 2000, 2000年

Reactive nitrogen over tropical ozone, reactive nitrogen, and CO observed over western and tropical Pacific Ocean in September-October 1998/1999　　　　　　　　　　　　　　　
Y. Kondo; M. Koike; H. Ikeda; H. Irie; K. Kita; Y. Zhao; T. Machida; D. Blake; B. Liley; S. Kawakami; T. Ogawa
Proceedings of Quadrennial Ozone Symposium Sapporo 2000, 2000年

High concentrations of ozone precursors observed in the upper troposphere over East Asia by aircraft measurements in April 1998　　　　　　　　　　　　　　　
Y. Miyazaki; K. Kita; Y. Kondo; S. Kawakami; T. Machida; D. Blake; N. Nishi; T. Ogawa
Proceedings of Quadrennial Ozone Symposium Sapporo 2000, 2000年

Ozonesonde observations in Indonesia during the BIBLE-A period　　　　　　　　　　　　　　　
M. Fujiwara; K. Kita; S. Kawakami; T. Ogawa; S. Saraspriya; T. Manik; A. Suripto; N. Komala; E. Kelana; T. Sribimawati; M. Kudsy; S. W; B. Harijono; M. D. Yamanaka
Proceedings of Quadrennial Ozone Symposium Sapporo 2000, 2000年

Reactive nitrogen over tropical Pacific: Influence from lightning and biomass burning　　　　　　　　　　　　　　　
M. Koike; Y. Kondo; D. Akutagawa; N. Takegawa; N. Nishi; S. C. Liu; K. Kita; D. Blake; T. Machida; B. Liley; S. Kawakami; W. Hu; M. Ko; T. Ogawa; N. Toriyama
Proceedings of Quadrennial Ozone Symposium Sapporo 2000, 2000年

Tropospheric ozone enhancements during the Indonesian forest fire events in 1994 and in 1997 as revealed by ground-based observations
M. Fujiwara; K. Kita; S. Kawakami; T. Ogawa; N. Komala; S. Saraspriya and A. Suriputo, Pronounced enhancements of total and tropospheric ozone were observed with the Brewer spectrophotometer and ozonesondes at Watukosek (7.5 degrees S, 112.6 degrees E), Indonesia in 1994 and in 1997 when extensive forest fires were reported in Indonesia. The integrated tropospheric ozone increased from 20 DU to 40 DU in October 1994 and to 55 DU in October 1997. On October 13, 1994, most ozone mixing ratios were more than 50 ppbv throughout the troposphere and exceeded 80 ppbv at some altitudes. On October 22, 1997, the concentrations were more than 50 ppbv throughout the troposphere and exceeded 100 ppbv at several altitudes. The coincidences of the ozone enhancements with the forest fires suggest the photochemical production of tropospheric ozone due to its precursors emitted from the fires for both cases. The years of 1994 and 1997 correspond to El Nino events when convective activity becomes low in Indonesia. Thus, in this region, it is likely that pronounced enhancements of tropospheric ozone associated with extensive forest fires due to sparse precipitation may take place with a period of a few years coinciding with El Nino events. This is in a marked contrast to the situation in South America and Africa where large-scale biomass burnings occur every year., AMER GEOPHYSICAL UNION
Geophys. Res. Lett., 1999年, ［査読有り］

Impact of aircraft emissions on NOx in the lowermost stratosphere at northern latitudes
Y. Kondo; M. Koike; H. Ikeda; B.E. Anderson; K. E. Brunke; Y. Zhao; K. Kita; T. Sugita; H.B. Singh; S.C; Liu; A. Thompson; G.L. Gregory; R. Shetter; G. Sachse; S.A. Vay; E.V. Browell; and M.J. Mahoney, Airborne measurements of NOx, total reactive nitrogen (NOy), O-3, and condensation nuclei (CN) were made within air traffic corridors over the U.S. and North Atlantic regions (35-60 degrees N) in the fall of 1997. NOx and NOy data obtained in the lowermost stratosphere (LS) were examined using the calculated increase in NOy (Delta NOy) along five-day back trajectories as a parameter to identify possible effects of aircraft on reactive nitrogen. It is very likely that aircraft emissions had a significant impact on the NOx levels in the LS inasmuch as the NOx mixing ratios at 8.5-12 km were significantly correlated with the independent parameters of aircraft emissions, i.e., Delta NOy levels and CN values. In order to estimate quantitatively the impact of aircraft emissions on NOx and CN, the background levels of CN and NOx at O-3 = 100-200 ppbv were derived from the correlations of these quantities with Delta NOy. On average, the aircraft emissions are estimated to have increased the NOx and CN values by 130 pptv and 400 STP cm(-3), respectively, which corresponds to 70+/-30 % and 30+/-20 % of the observed median values., AMER GEOPHYSICAL UNION
Geophys. Res. Lett., 1999年, ［査読有り］

An assessment of aircraft as a source of particles to the upper troposphere
B.E. Anderson; W.R. Cofer; J. Crawford; G.L. Gregory; S.A. Vay; K.E. Brunke; Y. Kondo; M. Koike; H. Schlager; S.L. Baughcum; E. Jensen; Y. Zhao; and K. Kita, Condensation nuclei measurements are examined in conjunction with measurements of reactive nitrogen species (NO(y)) to identify aircraft plumes in primary air traffic corridors over the North Atlantic. Several hundred plumes exhibiting greater than or equal to 100 pptv enhancements in NO(y) mixing ratio were observed. The plumes were typically a few hundred meters wide, exhibited high NO/NO(y) ratios, and ranged in age from similar to 10 minutes to similar to 10 hours. Assuming the sampled aircraft emitted similar to 12 g NO(x) (as NO(2)) kg(-1) fuel burned and that the loss of NO, to the particle phase was negligible, we calculate median aerosol emission indices in terms of number of particles kg(-1) of fuel burned of similar to 120 x 10(15) for CN greater than or equal to 8 nm in size; similar to 50 x 10(15) for CN greater than or equal to 17 nm; and similar to 3 x 10(15) for the nonvolatile CN greater than or equal to 17 nm. Using published fuel burn statistics, background aerosol concentrations, and a 10 day particle lifetime, we conclude that present aviation sources enhance global averaged upper-tropospheric fine and nonvolatile aerosol number densities by similar to 6% and similar to 3%, respectively., AMER GEOPHYSICAL UNION
Geophys. Res. Lett., 1999年, ［査読有り］

Stratosphere-troposphere exchange of ozone associated with the equatorial Kelvin wave as observed with ozonesondes and rawinsondes
M. Fujiwara; K. Kita and T. Ogawa, An intensive observation with ozonesondes and rawinsondes was conducted in Indonesia in May and June 1995 to investigate a phenomenon of ozone enhancement in the tropical upper troposphere. We obtained the characteristics of an enhancement that continued for about 20 days, concurring with a zonal wind oscillation associated with the equatorial Kelvin wave around the tropopause and the Madden-Julian oscillation (MJO) in the troposphere. The isoline of ozone mixing ratio of 40 nmol/mol moved by 5.0 km downward from 17.8 km to 12.8 km, while the tropopause height was 16.2-17.8 km throughout the period. Moreover, the maximum ozone concentration of 300 nmol/mol at the tropopause was concurrent with the maximum eastward wind phase of the Kelvin wave. The detailed mechanism of the ozone transport is interpreted as follows: The downward motion associated with the Kelvin wave and the MJO transported the stratospheric ozone into the troposphere, and the air mixing due to the Kelvin wave breaking at the tropopause also caused stratosphere-troposphere exchange. The upper limit of the net amount of ozone transported from the stratosphere was estimated to be 9.9 Dobson units with the zonal and meridional extents of the ozone-increased region of more than 6.6 x 10(6) m and 1.8 x 10(6) m, respectively, to imply the potential to affect the photochemistry around the tropical tropopause., AMER GEOPHYSICAL UNION
J. Geophys. Res., 1998年, ［査読有り］

Tropospheric ozone over Pacific and Indonesian Region: Relation with ENSO activity and a preliminary report on BIBLE aircraft campaign　　　　　　　　　　　　　　　
K. Kita; M. Fujiwara; Y. Miyazaki; S. Kawakami; T. Ogawa; N. Komala; S. Saraspriya; Y. Kondo; M. Koike; T. Machida; B. Liley; D. Blake; M. Watanabe; N. Nishi
Proceedings of International symposium on tropospheric ozone in East Asia and its potential impacts on vegetation, 1998年

Gravity wave signature simultaneously observed in the oxygen atom and electron density profiles in the lower thermosphere
T. Imamura; K. Kita; N. Iwagami and T. Ogawa, The fine structures of lower thermospheric atomic oxygen and electron density profiles obtained by a rocket experiment were investigated, assuming that these structures are due to a quasimonochromatic internal gravity wave, The height variation of the horizontal wind amplitude is similar to that of the intrinsic horizontal phase speed below similar to 105 km, implying an evidence of saturation effects. At higher altitudes. the dissipation due to molecular diffusion was suggested. The wavy variation of the intrinsic horizontal phase speed with height can be explained by the mean wind modulation due to an atmospheric tide, The horizontal phase velocity vector inferred is interpreted as a consequence of selective transmission of internal gravity waves in lower atmosphere. (C) 1997 COSPAR., PERGAMON PRESS LTD
Adv. in Space Res., 1997年, ［査読有り］

Carbon monoxide column abundance and tropospheric concentrations retrieved from high resolution ground-based infrared solar spectra at 43.5N over Japan
Y. Zhao; Y. Kondo; F.J. Murcray; X. Liu; M. Koike; K. Kita; H. Nakajima; I. Murata and K. Suzuki, High spectral resolution (0.0024 cm(-1)), ground-based infrared (IR) solar spectra were recorded at Rikubetsu, Japan (43.5 degrees N, 143.8 degrees E), by a Fourier transform infrared (FTIR) spectrometer covering the 4.8-mu m fundamental absorption band of carbon monoxide (GO). Total vertical CO columns and tropospheric concentrations, from May 1995 to May 1996, were retrieved from these spectra using an iterative inversion algorithm. Microwindows at 2111,00-2112.00 cm(-1) and 2157.40-2159.20 cm(-1) were used for the retrievals, Tropospheric CO concentrations above Rikubetsu retrieved from the IR solar spectra are in good agreement with aircraft measurements performed in the nearby area in recent years. The data exhibit seasonal variations in tropospheric CO concentrations. The averaged mixing ratios between 0 and 3 km are 219 +/- 26 parts per billion by volume (ppbv) in April and 115 +/- 7 ppbv in September. The data also show CO concentrations and seasonal variations decreasing with altitude. The vertical change in CO concentration is the greatest in spring and the smallest in fall. A maximum CO column of 3.31 +/- 0.34 x 10(18) molecules cm(-2) in April and a minimum of 2.04 +/- 0.10 x 10(18) molecules cm(-2) in September were observed. The CO column above Rikubetsu is consistent with observations at Kitt Peak, the International Scientific Station of the Jungfraujoch (ISSJ), and Zvenigorod, considering differences in altitude and latitude between the observatories., AMER GEOPHYSICAL UNION
J. Geophys. Res., 1997年, ［査読有り］

OI 630 nm nightglow depletion observations at Watukosek, Indonesia
K. Shibasaki; K. Kita; N. Iwagami; T. Ogawa; and A. Sriputo, We present the OI 630.0 nm night airglow (nightglow) observation data obtained with a groundbased scanning photometer at Watukosek (7.6 degrees S, 112.7 degrees E), Indonesia. We made the first observation in December, 1986 in order to study ionospheric F region plasma behavior from the ground. The airglow pattern over equatorial anomaly region is closely related to the distribution of equatorial F region electron density. Plasma turbulence in ionospheric F layer can be reflected on space configurations for OI 630.0 nm airglow emission; plasma bubbles are observed as structured depletion regions in nightglow intensity. During the second observation campaign of September 26, 27, and 28, 1989, we observed multiple depletion structures in intensity of OI 630.0 nm nightglow moving eastward. We measured almost the same depletion feature at two directions, zenith and 30 degrees north from the zenith. We suggest that we observed the nearly field-aligned depletion structures. In 1993 from May through November we made nightglow observations for 46 nights. However, we observed few distinct phenomena such as plasma bubbles. Plasma drift velocities derived from these measurements of nightglow depletion events are presented and briefly discussed., TERRA SCIENTIFIC PUBL CO
J. Geomag. Geoelectr., 1997年, ［査読有り］

Variability of oxygen atom concentration in the lower thermosphere observed by rocket experiments
K. Kita; T. Imamura; N. Iwagami; W. H. Morrow and T. Ogawa, 筆頭著者, A series of rocket experiments was carried out to observe altitude profiles of oxygen atom density and oxygen night airglows at Uchinoura (31 degrees N). In the last rocket experiment, S310.21 launched on 28 Jan 1992, the attitude profile of oxygen atom density between 75 km and 200 km was observed with an improved resonant fluorescence instrument developed to avoid the Doppler effect and the aerodynamic shock effect due to the supersonic motion of a rocket. The altitude profile of the OI green line emission rate was simultaneously observed. Comparing the observed profiles, quantitative relations between oxygen atom density and the oxygen airglows are examined, and oxygen atom density is evaluated from the measured airglow profiles. The evaluated profiles of oxygen atom concentration show a significant variability. The variability should be attributed to variation of dynamical transport in this region., PERGAMON PRESS LTD
Adv. in Space Res., 1996年, ［査読有り］

Rocket observation of atomic oxygen and night airglow: Measurement of concentration with an improved resonance fluorescence technique
K. Kita; T. Imamura; N. Iwagami; W. H. Morrow and T. Ogawa, 筆頭著者, An improved resonant fluorescence instrument for measuring atomic oxygen concentration was developed to avoid the Doppler effect and the aerodynamic shock effect due to the supersonic motion of a rocket. The shock effect is reduced by adopting a sharp wedge-shaped housing and by scanning of the detector field of view to change the distance between the scattering volume and the surface of the housing. The scanning enables us to determine absolute values of atomic oxygen concentration from relative variation of the scattered light signal due to the self-absorption. The instrument was calibrated in the laboratory, and the numerical simulation reproduced the calibration result. Using the instrument, the altitude profile of atomic oxygen concentration was observed by a rocket experiment at Uchinoura (31 degrees N) on 28 January 1992. The data obtained from the rocket experiment were not perfectly free from the shock effect, but errors due to the effect were reduced by the data analysis procedure. The observed maximum concentration was 3.8 x 10(11) cm(-3) at altitudes around 94 km. The systematic error is estimated to be less than +/- 0.7 x 10(11) cm(-3) and the relative random error is less than +/- 0.07 x 10(11) cm(-3) at the same altitudes. The altitude profile of the OI 557.7-nm airglow was also observed in the same rocket experiment. The maximum volume emission rate was found to be 150 photons cm(-3) s(-1) at 94 km. The observed altitude profiles are compared with the MSIS model and other in situ observations., SPRINGER VERLAG
Ann. Geophys., 1996年, ［査読有り］

Tropospheric ozone behavior in Indonesia
Ninong-Komala; Slamet-Saraspriya; K. Kita and T. Ogawa, 筆頭著者, The variation of the surface and free tropospheric ozone has been observed at Watukosek (7.5 degrees S, 112.6 degrees E), Indonesia. This paper is to report the analysis of the ozonesonde data obtained during the period November 1992-June 1994. A seasonal variation of ozone is evident in the lower and middle troposphere, with the maximum occurring in September and October. In the upper troposphere, seasonal variation is not evident, but enhancements were occasionally detected in April, May and June. A common feature that ozone mixing ratio is nearly constant of 20-30 ppbv throughout the troposphere is identified as a basic type of altitude profile appearing in the wet season, December through March, and in the middle of the dry season, July and August. Two other features are occasionally found. One appearing in April, May and June exhibits an enhancement over 50 ppbv in the upper troposphere, and the other appearing in September and October exhibits an enhancement in the lower and middle troposphere., PERGAMON-ELSEVIER SCIENCE LTD
Atmos. Environ., 1996年, ［査読有り］

Atomic oxygen 630 nm and OH airglows at Mt. Haleakala, Hawaii in February and November 1993
Y. Kiyama; K. Kita; N. Iwagami and T. Ogawa, Temporal variations of the all-sky distribution of atomic oxygen 630 nm airglow intensity were observed at Mt. Haleakala in Maui Island, Hawaii, to obtain information on the dynamics of F region plasma in the equatorial anomaly region. All-sky intensity distribution of the hydroxyl OH(7,2) band airglow originating from the mesopause region was simultaneously observed to seek any relationship between the dynamical variations off region plasma and the disturbance in the lower atmosphere. The results of our preliminary analyses of the data obtained in February and November 1993 show that there is no definite correlation in the patterns of all-sky intensity distribution between atomic oxygen 630 nm and OH(7,2) band airglows in both geomagnetically disturbed and quiet nights. The all-sky intensity pattern of 630 nm is found to be modified during a geomagnetic storm, while that of OH(7,2) band varies independently of geomagnetic activity., TERRA SCIENTIFIC PUBL CO
J. Geomag. Geoelectr., 1996年, ［査読有り］

Gravity wave characteristics derived from structured atomic oxygen profile and multiple Es layers
T. Imamura; K. Kita and T. Ogawa, We investigated the fine structures of lower thermospheric atomic oxygen and electron density profiles obtained by a rocket experiment, assuming that these structures are due to a quasi-monochromatic internal gravity wave. The dissipation process of a gravity wave was inferred from the atomic oxygen profile. The height variation of the horizontal wind amplitude is similar to that of the intrinsic horizontal phase speed below similar to 105 km, implying an evidence of saturation effects. At higher altitudes, dissipation due to molecular diffusion was suggested. The propagation direction of the wave was determined from both atomic oxygen and electron profiles based on the fact that the response of ionic species to gravity waves is different from that of neutral species depending on the propagation direction. The propagation direction inferred is interpreted as a consequence of selective transmission of gravity waves in lower atmosphere., TERRA SCIENTIFIC PUBL CO
J. Geomag. Geoelectr., 1995年, ［査読有り］

Polar thermosphere-stratosphere photochemical coupling experiment: Preliminary results of a rocket experiment　　　　　　　　　　　　　　　
N. Iwagami; K. Kita; H. Yamamoto; T. Makino; H. Sekiguchi; T. Watanabe; K. Suzuki; K. Shibasaki; H. Amemiya; T. Ono
Proceeding of 8th International Symposium of Solar Terrestrial Physics in Sendai, 1994年06月

Nitric oxide variability in the lower thermosphere at low latitudes
N. Iwagami; K. Kita; T. Ogawa; and K. S. Zalpuri, PERGAMON PRESS LTD
Adv. Space Res., 1993年, ［査読有り］

Rocket observations of oxygen night airglows: Excitation mechanisms and oxygen atom concentration
K. Kita; N. Iwagami and T. Ogawa, 筆頭著者, The altitude profiles of oxygen night airglows were observed by rocket experiments at Uchinoura (31-degrees-N). Simultaneous measurements of emission rates at three different bands of the O2 Herzberg I system, originating from higher, middle and lower vibrational levels of O2(A3SIGMA(u)+), suggests that the vibrational distribution of O2(A3SIGMA(u)+) is almost invariant in the night airglow and that it varies considerably in the rocket glow. This result is explained by a model for the excitation and de-excitation of the Herzberg I system, where O2(A3SIGMA(u)+) is assumed to be excited directly in the three-body recombination of oxygen atoms and to be de-excited mainly due to collisions with atmospheric molecules. A possible range of the rate coefficients of the O2(A3SIGMA(u)+) de-excitation is determined to be compatible with the observation. Based on the inferred excitation mechanisms, oxygen atom concentration is deduced from the observed emission rates of the Herzberg I bands within a systematic error of factor 2 approximately 4 in terms of its absolute value and within an error around 20 % in terms of its relative value. The OI green line airglow at 557.7 nm and the O2 Infrared Atmospheric (0,0) band airglow at 1.27 mum were observed simultaneously with the Herzberg I bands, and their excitation mechanisms axe also discussed. The excitation mechanism of the green line is confirmed to be the two-step process. The O2 Infrared Atmospheric system is excited via the three-body recombination of oxygen atoms in an altitude region above approximately 90 km, whereas it is likely to be excited mostly by another mechanism below approximately 90 km., PERGAMON-ELSEVIER SCIENCE LTD
Planet. Space Sci., 1992年, ［査読有り］

Variability of stratospheric NO2 profiles at northern middle latitudes, in Ozone in the Atmosphere　　　　　　　　　　　　　　　
Shibasaki, K; N. Iwagami; K. Kita; T. Ogawa, A. Deepak Publishing
R. D. Bojkov and P. Fabian (eds.), 1989年01月

Bayesian statistical inference on airglow profiles from rocket observational data: comparison with conventional methods
K. Kita; T. Higuchi and T. Ogawa, 筆頭著者, PERGAMON-ELSEVIER SCIENCE LTD
Planet. Space Sci., 1989年, ［査読有り］

Thermospheric NO Measurement at Solar Minimum
K. KITA; N. IWAGAMI; T. OGAWA, TERRA SCIENTIFIC PUBL CO
Journal of geomagnetism and geoelectricity, 1988年01月, ［査読有り］

Height distributions of the night airglow emissions in the O2 Herzberg I system and oxygen green line from a simultaneous rocket observation
K. Kita; N. Iwagami; T. Ogawa; A. Miyashita and H. Tanabe, 筆頭著者, TERRA SCIENTIFIC PUBL CO
J. Geomag. Geoelectr., 1988年, ［査読有り］

Bayesian statistical inference to remove periodic noise in the optical observations aboard a spacecraft
T. Higuchi; K. Kita and T. Ogawa, OPTICAL SOC AMER
Applied Optics, 1988年, ［査読有り］

蛍光を用いた放射性微粒子(CsMP)の検出可能性
北和之; 阿部善也; 末木啓介; 佐藤志彦; 五十嵐康人
日本放射化学会討論会(Web), 2022年

フィルタサンプリングおよび蛍光スペクトル測定によるバイオエアロゾル定量法の開発
北和之; 関口碧; 川上花音; 南尾健太; 牧輝弥; 保坂健太郎; 五十嵐康人
日本地球惑星科学連合大会予稿集(Web), 2022年

福島高セシウム沈着地域での事故後10年間の大気放射能濃度変化
北和之; 林奈穂; TANG Peng; 畑中恒太郎; 木名瀬健; 足立光司; 財前祐二; 石塚正秀; 古川純; 羽田野祐子; 末木啓介; 恩田裕一; 二宮和彦; 篠原厚; 豊田栄; 山田桂太; 吉田尚弘; 佐藤志彦; 五十嵐康人
日本地球惑星科学連合大会予稿集(Web), 2021年

植物園林内におけるリアルタイム浮遊菌カウンタによる微生物粒子の計測
渡辺幸一; 牧輝弥; 保坂健太郎; 北和之; 五十嵐康人
エアロゾル科学・技術研究討論会(CD-ROM), 2021年

森林内外を浮遊するバイオエアロゾルの季節的変動の解明
牧輝弥; 保坂健太郎; 三星かおり; 北和之; 五十嵐康人
エアロゾル科学・技術研究討論会(CD-ROM), 2021年

福島第一原発事故由来の放射性Cs微粒子の蛍光特性
阿部善也; 阿部善也; 小野崎晴佳; 石川真帆; 中井泉; 北和之; 五十嵐康人; 五十嵐康人; 大浦泰嗣; 鶴田治雄; 森口祐一
日本放射化学会討論会(Web), 2020年

降水で発生する生態学的セシウム再浮遊-粗大バイオエアロゾル
五十嵐康人; 木名瀬健; 北和之; 林菜穂; 石塚正秀; 足立光司; 小板橋基夫; 関山剛; 恩田裕一
日本放射化学会討論会(Web), 2020年

緩和渦集積法を用いたバイオエアロゾルフラックスの測定システムの開発
反町篤行; 北和之; 五十嵐康人; 保坂健太郎; 南光太郎; 堅田元喜; 羽田野裕子; 池田遼
大気環境学会年会講演要旨集, 2018年08月28日

茨城大学-フランス放射線防護原子力安全研究所(IRSN) 国際ワークショップ開催報告 ｢大気放射性セシウムとバイオエアロゾルの放出｣
北 和之; 五十嵐 康人
日本原子力学会誌ATOMOΣ, 2018年

福島県浪江町の里山における大気エアロゾル中放射性セシウム濃度に及ぼす山林火災の影響
吉岡颯; 大河内博; CHO Gai; 勝見尚也; 二宮和彦; 北和之; 五十嵐康人
日本地球惑星科学連合大会予稿集(Web), 2018年

福島高線量地区における夏季大気セシウム放射能濃度増加とバイオエアロゾル
北和之; 林奈穂; 南光太郎; 木村茉央; 五十嵐康人; 足立光司; 牧輝弥; 石塚正秀; 大河内博; 古川純; 二宮和彦; 篠原厚
日本地球惑星科学連合大会予稿集(Web), 2018年

シイタケ胞子の飛散機構の解明に向けた基礎的実験―胞子の形状特性の観察―
石塚正秀; 田中邦明; 五十嵐康人; 保坂健太郎; 北和之
日本地球惑星科学連合大会予稿集(Web), 2018年

2013年茨城県つくば市における大気Cs‐137濃度変動とバイオエアロゾルによる寄与
林奈穂; 北和之; 五十嵐康人; 足立光司; 木村徹
日本地球惑星科学連合大会予稿集(Web), 2018年

降水時の森林からのバイオエアロゾル放出源変化
林奈穂; 北和之; 五十嵐康人; 牧輝也; 小板橋基夫
エアロゾル科学・技術研究討論会(CD-ROM), 2018年

つくば実験植物園でのバイオエアロゾル観測
五十嵐康人; 北和之; 牧輝弥; 保坂健太郎; 反町篤行; 羽田野祐子; 石塚正秀; 齊藤保典; 川端康弘; 大河内博; 白石浩一; 冨田孝幸; 足立光司; 財前祐二; 水谷耕平; 河村公隆
エアロゾル科学・技術研究討論会(CD-ROM), 2018年

大気エアロゾル中の菌類胞子有機物トレーサーと¹³⁷Csの関係:福島県で採取した昼夜試料の解析結果
河村公隆; KUNWAR B; 北和之; 五十嵐康人
日本地球化学会年会要旨集(Web), 2018年

boxモデルを用いた福島事故由来のCs‐137大気再飛散の解析
中村祐太; 羽田野祐子; 北和之; 五十嵐康人; 梶野瑞王; 石塚正秀
KEK Proceedings (Web), 2017年11月

降水によるエアロゾル発生現象?:大気‐森林相互作用の新展開をねらって
五十嵐康人; 北和之; 牧輝弥; 齊藤保典; 大河内博; 保坂健太郎; 白石浩一; 冨田孝幸; 足立光司; 財前祐二
エアロゾル科学・技術研究討論会(CD-ROM), 2017年

福島森林域でのバイオエアロゾルの観察―放射性セシウムの大気再飛散担体の可能性
林奈穂; 北和之; 五十嵐康人; 足立光司; 木村徹; 牧輝弥; 二宮和彦; 篠原厚; 豊田栄; 石塚正秀
エアロゾル科学・技術研究討論会(CD-ROM), 2017年

夏季‐秋季における放射性セシウム大気再飛散のメカニズム
西岡拓哉; 北和之; 林奈穂; 佐藤武尊; 五十嵐康人; 足立光司; 財前祐二; 豊田栄; 山田桂太; 吉田尚弘; 牧輝弥; 石塚正秀; 二宮和彦; 篠原厚; 大河内博; 阿部善也; 中井泉; 川島洋人; 古川純; 羽田野祐子; 恩田裕一
日本地球惑星科学連合大会予稿集(Web), 2017年

大気中Cs‐137濃度の長期予測モデル式の提案とAICによる評価
小西将貴; 羽田野祐子; 五十嵐康人; 北和之
KEK Proceedings (Web), 2016年10月

放射性セシウムの大気への再浮遊にバイオエアロゾルが果たす役割
五十嵐康人; 北和之; 牧輝弥; 竹中千里; 木名瀬健; 足立光司; 梶野瑞王; 関山剛; 財前祐二; 石塚正秀; 二宮和彦; 大河内博; 反町篤行
日本気象学会大会講演予稿集, 2016年09月30日

福島第一原発事故由来放射性セシウムの再浮遊:バイオエアロゾルの役割?
五十嵐康人; 北和之; 牧輝弥; 竹中千里; 木名瀬健; 足立光司; 梶野瑞王; 関山剛; 財前祐二; 石塚正秀; 二宮和彦; 大河内博; 反町篤行
エアロゾル科学・技術研究討論会(CD-ROM), 2016年08月31日

福島第一原子力発電所事故による放射性物質の大気環境影響調査研究の現状と課題
鶴田 治雄,五十嵐 康人,井上 智博,大河内 博,大原 利眞,梶野 瑞王,兼保 直樹,北 和之,反町 篤行,平木 隆年,堀江 洋佑,森口 祐一,森野 悠,渡邊 明
大気環境学会誌, 2016年03月10日

原発事故由来の放射性セシウム大気濃度の長期解析:土壌,植物からの再飛散
梶野瑞王; 梶野瑞王; 石塚正秀; 五十嵐康人; 北和之; 吉川知里; 稲津將
日本地球惑星科学連合大会予稿集(Web), 2016年

福島第一原発事故由来放射性セシウムの再浮遊:胞子は重要な役割を果たすのか?
五十嵐康人; 北和之; 牧輝弥; 竹中千里; 木名瀬健; 足立光司; 梶野瑞王; 関山剛; 財前祐二; 石塚正秀; 二宮和彦; 大河内博; 反町篤行
日本地球惑星科学連合大会予稿集(Web), 2016年

夏/秋季における大気中の放射性セシウムの再飛散過程~生物‐大気循環の可能性
北和之; 木名瀬健; 堀内貴明; 坂本宗一郎; 武井愛里; 出水宏幸; 五十嵐康人; 足立光司; 梶野瑞王; 山田桂太; 豊田栄; 吉田尚弘; 二宮和彦; 篠原厚; 大河内博; 緒方裕子; 石塚正秀; 牧輝弥; 阿部善也; 中井泉; 古川純; 恩田裕一
日本地球惑星科学連合大会予稿集(Web), 2016年

ICP‐MS直接エアロゾル元素分析による野外観測の試み
五十嵐康人; 西口講平; 萩野浩之; 木名瀬健; 北和之
日本地球化学会年会講演要旨集, 2015年09月16日

放射性セシウムの大気再飛散担体粒子の解明
北和之; 田村匠; 田中美佐子; 木野日美子; 木名瀬健; 出水宏幸; 足立光司; 財前祐二; 五十嵐康人; 豊田栄; 山田桂大; 吉田尚弘; 二宮和彦; 阿部善也; 中井泉; 大河内博; 石塚正秀; 恩田裕一
日本地球惑星科学連合大会予稿集(Web), 2015年

東京で観測されたBCの被覆状態と光吸収係数の変化
青木春樹; 北和之; 茂木信宏; 大畑祥; 足立光司; 五十嵐康人; 小池真; 近藤豊
日本地球惑星科学連合大会予稿集(Web), 2015年

137Cs及び134Csの大気中放射能濃度と粒径分布の季節変動
木名瀬健; 北和之; 田中美佐子; 出水宏之; 五十嵐康人; 足立光司; 三上正男; 山田桂太; 豊田栄; 吉田尚弘; 篠原厚; 二宮和彦; 大河内博; 石塚正秀; 川島洋人; 中井泉; 阿部善也; 恩田裕一
日本地球惑星科学連合大会予稿集(Web), 2015年

福島第一原子力事故初期に採取された大気試料中の¹⁴⁰Baの分析
張子見; 二宮和彦; 北和之; 鶴田治雄; 五十嵐康人; 篠原厚
日本放射化学会年会・放射化学討論会研究発表要旨集, 2014年09月11日

P235 リモートセンシングによる下部対流圏オゾン量導出のための航空機による検証観測(ポスターセッション)
谷中 郁哉; 北 和之; 山口 裕樹; 福寿 旅人; 板橋 良平; 木名瀬 健; 入江 仁士; 野口 克行; 中山 智喜; 松見 豊; 永井 智広; 酒井 哲; 財前 祐二; 森野 勇; 田中 智章
大会講演予講集, 2014年04月30日

B306 福島およびその周辺4地点における大気エアロゾル中のCs-137濃度の3年間の長期変化(物質循環,一般口頭発表)
鶴田 治雄; 司馬 薫; 山田 裕子; 草間 優子; 荒井 俊昭; 渡邊 明; 長林 久夫; 北 和之; 篠原 厚; 二宮 和彦; 横山 明彦; 末木 啓介; 本多 照幸; 桧垣 正吾; 梶野 瑞王; 中島 映至
大会講演予講集, 2014年04月30日

P3a4 静止衛星を用いた対流圏NO_2観測における地表面BRDFの影響 : 鉛直気柱量の評価(ポスター・セッション)
野口 克之; リヒター アンドレアス; バローズ ジョン・P; 入江 仁士; 北 和之
大会講演予講集, 2014年

C204 大気中放射性物質濃度変動特徴(物質循環II,口頭発表)
渡辺 明; 桧垣 正吾; 篠原 厚; 鶴田 治雄; 北 和之; 吉田 尚弘
大会講演予講集, 2013年10月31日

地表面から飛散したダスト粒子による再浮遊放射性物質の一次元推定
石塚正秀; 三上正男; 田中泰宙; 五十嵐康人; 北和之; 吉田尚弘; 豊田栄; 篠原厚
日本気象学会大会講演予稿集, 2013年10月31日

福島第一原発事故による大気環境影響の研究:つくばでの2か年にわたる観測
五十嵐康人; 財前祐二; 足立光司; 梶野瑞王; 羽田野祐子; 北和之
エアロゾル科学・技術研究討論会, 2013年08月27日

P319 リモートセンシングによる下部対流圏オゾン量導出のための検証観測(ポスター・セッション)
山口 裕樹; 福寿 旅人; 北 和之; 板橋 良平; 木名 瀬健; 谷中 郁哉; 入江 仁士; 野口 克行; 中山 智喜; 松見 豊; 永井 智広; 酒井 哲; 財前 祐二; 森野 勇; 田中 智章
大会講演予講集, 2013年04月30日

D207 放射性物質降下量の変動特性について(物質循環I,口頭発表)
渡辺 明; 桧垣 正吾; 篠原 厚; 鶴田 治雄; 北 和之; 吉田 尚弘
大会講演予講集, 2013年04月30日

福島第一原子力発電所事故により放出された放射性セシウムの大気再飛散メカニズムと飛散係数推定
北和之; 田中美佐子; 佐藤かおり; 木名瀬健; 出水宏幸; 五十嵐康人; 三上正男; 吉田尚弘; 豊田栄; 山田桂大; 篠原厚; 川島洋人; 大河内博; 恩田裕一
日本気象学会大会講演予稿集, 2013年04月30日

P101 Nd:YAGレーザーを用いた二酸化窒素観測用ライダーの開発(II)(ポスター・セッション)
永井 智広; 酒井 哲; 真野 裕三; 中里 真久; 内野 修; 入江 仁士; 北 和之
大会講演予講集, 2012年09月30日

福島第一原発事故後の大気放射性物質の変動と土壌からの再飛散の影響
北和之; 田中美佐子; 佐藤ゆかり; 出水宏幸; 渡邊明; 鶴田治雄; 植松光夫; 桧垣正吾; 吉田尚弘; 豊田栄; 山田桂大; 篠原厚; 三上正男; 五十嵐康人; 恩田裕一; 末木啓介; 滝川雅之; 長林久夫; 横山明彦
大気環境学会年会講演要旨集, 2012年08月29日

D461 福島における放射性物質の降下量の変動(物質循環,一般口頭発表)
渡辺 明; 桧垣 正吾; 篠原 厚; 鶴田 治雄; 北 和之
大会講演予講集, 2012年04月30日

B103 Nd:YAGレーザーを用いた二酸化窒素観測用ライダーの開発(観測手法,一般口頭発表)
永井 智広; 酒井 哲; 真野 裕三; 中里 真久; 内野 修; 入江 仁士; 北 和之
大会講演予講集, 2011年10月31日

大気放射性物質の広域観測と土壌からの再飛散の影響
北 和之、笠原理絵、渡邊 明、鶴田治雄、植松光夫、桧垣正吾、吉田尚弘、豊田 栄、山田桂大、篠原 厚、三上正男、五十嵐康人、恩田裕一、末木啓介、滝川雅之ほか、日本地球化学会=日本地球惑星科学連合=日本放射化学会連携緊急放射性物質サンプリングチーム大気班および分析班
大会講演予講集,100, 2011年10月31日

大気放射性物質の広域観測と土壌からの再飛散の影響
北和之; 笠原理絵; 鶴田治雄; 桧垣正吾; 吉田尚弘; 豊田栄; 山田桂大; 篠原厚; 三上正男; 五十嵐康人; 恩田裕一; 末木啓介
日本気象学会大会講演予稿集, 2011年10月31日

P213 太陽散乱光の可視-紫外同時分光観測による下部対流圏オゾン量の推定(ポスターセッション)
北 和之; 大竹 翔; 仲地 正樹; 入江 仁士; 中里 真久
大会講演予講集, 2010年

P175 太陽散乱光の可視-紫外同時分光観測による下部対流圏オゾン量の推定 2 : 筑波山頂からの予備観測(ポスター・セッション)
北 和之; 大竹 翔; 仲地 正樹; 入江 仁士; 中里 真久
大会講演予講集, 2010年

気球光学オゾンゾンデとECCゾンデによるJEM/SMILES観測検証実験
笠井康子; 入交芳久; 落合啓; 村山泰啓; 村田功; 佐藤薫; 冨川喜弘; 北和之; 岡野章一
大気球シンポジウム: 平成21年度, 2009年10月

「成層圏過程とその気候影響(SPARC)」計画の活動紹介
林田 佐智子; 小寺 邦彦; 秋吉 英治; 今村 隆史; 岩崎 俊樹; 笠井 康子; 北 和之; 小池 真; 佐藤 薫; 塩谷 雅人; 柴田 清孝; 津田 敏隆; 廣岡 俊彦; 藤原 正智; 村山 泰啓; 余田 成男; 堤 雅基
天気, 2007年11月30日

夏季-秋季の日光白根山におけるオゾンの観測 : 2002年と2004年の比較
畠山 史郎; 高見 昭憲; 片平 菊野; 高山 悟; 北 和之
天気, 2006年03月31日

P107 航空機リモートセンサAirborne-OPUSによる紫外後方散乱スペクトルからのオゾンカラム量導出及び誤差要因の検討
仲田 季寧; 北 和之; 鈴木 睦; 塩見 慶; 奥村 真一郎
大会講演予講集, 2006年

C301 航空機リモートセンサAirborne-OPUSによる紫外後方散乱スペクトルからのオゾンカラム量導出(物質循環III)
仲田 季寧; 北 和之; 鈴木 睦; 塩見 慶; 奥村 真一郎
大会講演予講集, 2005年

C209 夏季～秋季の日光白根山におけるオゾンの観測 : 2002年と2004年の比較(スペシャルセッション「高所山岳を利用した大気科学の展望:富士山頂を観測拠点に」)
畠山 史郎; 高見 昭憲; 片平 菊野; 高山 悟; 北 和之
大会講演予講集, 2005年

D304 春季西太平洋域で観測された自由対流圏中での人為起源物質の増大(その3) : PEACE-B航空機観測(物質循環II)
大島長; 小池真; 中村尚; 近藤豊; 竹川暢之; 宮崎雄三; BlakeD. R; 白井知子; 北和之; 川上修司; 小川利紘
大会講演予講集, 2004年05月

D362 春季西太平洋域で観測された自由対流圏中での人為起源物質の増大(その2) : PEACE-B航空機観測(物質循環III)
大島長; 小池真; 近藤豊; 北和之; 竹川暢之; 宮崎雄三; 中村尚; BlakeD. R; 白井知子; 井上修司; 小川利紘
大会講演予講集, 2003年10月15日

Asian outflow to the Pacific observed during PEACE aircraft campaign in 2002
M Koike; Y Kondo; N Oshima; N Takegawa; K Kita; H Nakamura; Y Miyazaki; DR Blake; T Shirai; S Kawakami; T Ogawa
GEOCHIMICA ET COSMOCHIMICA ACTA, 2003年09月

Photochemical ozone production in the Asian outflow to the Pacific observed during PEACE aircraft campaign
K Kita; Y Kondo; A Koike; N Takegawa; K Nakamura; DR Blake; T Shirai; S Kawakami; T Ogawa
GEOCHIMICA ET COSMOCHIMICA ACTA, 2003年09月

Correlation of CO and CO2 in Asian outflow plumes observed during PEACE campaign in January 2002
N Takegawa; Y Kondo; T Machida; T Watai; M Koike; K Kita; DR Blake; S Kawakami; T Ogawa
GEOCHIMICA ET COSMOCHIMICA ACTA, 2003年09月

TRACE-Pで観測された窒素酸化物と硝酸塩エアロゾルの関係
山崎 淳; 近藤 豊; 小池 真; 北 和之; 竹川 暢之; 池田 響; 宮崎 雄三; 升井 幸男; 入江 仁士; TRACE-Pサイエンスチーム
大会講演予講集, 2002年05月

Air-borne OPUSによる三宅島・桜島SO_2観測
渡辺 征春; 奥村 真一郎; 鈴木 睦; 川上 修司; 吉田 重臣; 佐野 琢己; 小川 利紘; 畠山 史郎; 北 和之; 近藤 豊
大会講演予講集, 2002年05月

中緯度下部成層圏オゾン層状構造の解析II
冨川 喜弘; 藤原 正智; 北 和之; 佐藤 薫; 山森 美穂; 吉識 宗義
大会講演予講集, 1999年11月24日

インドネシア森林火災に伴う対流圏オゾン光化学生成
藤原 正智; 北 和之; 川上 修司; 小川 利紘
火災, 1998年04月20日

インドネシア森林火災に伴う対流圏オゾン光化学生成
藤原正智; 北和之; 川上修司; 小川利紘
火災（日本火災学会誌）, 1998年, ［招待有り］

Biomass burning in the Tropics and Tropospheric Ozone
K. Kita; M. Fujiwara; T. Ogawa
Global Environ. Res., 1998年
筆頭著者

TOMSデータから推定する対流圏オゾン変動
北 和之; 佐藤 尚毅; 平田 康之; 藤原 正智; 小川 利絋; 佐野 琢己
大会講演予講集, 1997年05月

赤道波動に伴う成層圏対流圏大気交換過程
藤原 正智; 北 和之; 小川 利絋
大会講演予講集, 1997年05月

1997年乾季におけるインドネシアの森林火災による対流圏オゾン増大
川上修司; 藤原正智; 北和之; 小川利紘; Slamet Saraspriya; Agus Suripto; Ninong Komala
日本リモートセンシング学会誌, 1997年

熱帯域バイオマス燃焼と対流圏オゾン
北 和之; 藤原正智; 小川利紘
地球環境, 1997年
筆頭著者

日本上空における一酸化炭素・オゾン濃度変動の航空機観測
北 和之; 藤原 正智; 平田 康之; 小川 利紘; 矢澤 健司; 田丸 卓
大会講演予講集, 1996年05月21日

地表境界層-自由対流圏間物質輸送の飛行船・航空機観測
平田 康之; 北 和之; 藤原 正智; 小川 利紘; 佐野 琢己; 矢澤 健司; 田丸 卓
大会講演予講集, 1996年05月21日

Total ozone enhancement in September and October 1994 in Indonesia
Fujiwara, M; K. Kita; T. Ogawa; N. Komala; S. Saraspriya; A. Suripto; T. Sano
Atmospheric Ozone (Proceedings of the XVIII Quadrennial Ozone Symposium, L'Aquila, Italy, September 12-21, 1996), 1996年01月

接地境界層における大気微量気体のフラックス測定法と評価法
原薗芳信; 文字信貴; 宮田 明; 北 和之; 鱧谷 憲; 内田洋平; 吉本真由美; 佐野琢己; 藤原正智; 磯辺誠之; 小川利紘
農業環境技術研究所報告, 1996年

インドネシアにおけるオゾンゾンデ観測
北 和之; 藤原 正智; 小川 利紘; KOMALA Ninong; SARASPRIYA Slamat; 前里 卓
大会講演予講集, 1995年05月15日

三陸における成層圏二酸化窒素, オゾン高度分布の大気球観測 -B15-64,66号機とオゾンゾンデ観測結果
柴崎和夫; 岩上直幹; 北 和之; 小川利紘
宇宙科学研究所報告, 1988年

同時ロケット観測による夜間大気光酸素分子ヘルツベルグI帯及び酸素原子557.7nm緑線の励起過程の研究
北 和之; 岩上直幹; 小川利紘; 宮下暁彦; 田辺浩義
宇宙科学研究所報告, 1988年
筆頭著者

Interlocal Adaptations to Climate Change in East and Southeast Asia,Sharing Lessons of Agriculture, Disaster Risk Reduction, and Resource Management
Do Duy Tung and Kazuyuki Kita, 分担執筆
Springer, 2022年01月
9783030812065

原発事故環境汚染―福島第一原発事故の地球科学的側面　　　　　　　　　　　　　　　
中島映至、大原利眞、植松光男、恩田裕一, 共著
東京大学出版会, 2014年

アサヒ・エコブックス 地球変動の最前線を訪ねる　　　　　　　　　　　　　　　
北 和之; 小川 利紘; 及川 武久; 陽 捷行, 共著
清水弘文堂書房, 2010年

太陽地球系科学　　　　　　　　　　　　　　　
日本地球電磁気・地球惑星圏学会 学校教育ワーキンググループ, 共著
京都大学学術出版会, 2010年

気象研究ノート 209号,先端質量分析技術による反応性大気化学組成の測定,第2章化学イオン化質量分析法による気体成分の測定　　　　　　　　　　　　　　　
北 和之、森野 悠、竹川暢之、廣川 淳、近藤 豊、小池 真、谷本浩志, 共著
日本気象学会, 2005年

気象研究ノート 209号 先端質量分析技術による反応性大気化学組成の測定 第2章化学イオン化質量分析法による気体成分の測定　　　　　　　　　　　　　　　
北 和之; 森野 悠; 竹川暢之; 廣川 淳; 近藤 豊; 小池 真; 谷本浩志, 共著
日本気象学会, 2005年

「対流圏光化学」、キーワード気象の事典　　　　　　　　　　　　　　　
北 和之; (新田 尚,伊藤朋之,住 明正,木村龍治,安成哲三編), 単著
朝倉書店, 2002年

Total ozone enhancement in September and October 1994 in Indonesia, in Atmospheric Ozone　　　　　　　　　　　　　　　
M. Fujiwara; K. Kita; T. Ogawa; N. Komala; S. Saraspriya; A. Suriputo; T. Sano, 共著
Parco Scientifico e Tecnologico d'Abruzzo, 1996年

Variability of stratospheric NO2 profiles at northern middle latitudes, in "Ozone in the Atmosphere"　　　　　　　　　　　　　　　
K. Shibasaki; N. Iwagami; K. Kita; T. Ogawa; R. D. Bojkov; P. Fabian, 共著
A. Deepak Publishing, 1989年

大気と植物・菌類との放射性セシウム移行可能性の研究　　　　　　　　　　　　　　　
北和之、 古川純、 根内水紀、 南尾健太、 羽田野祐子、 五十嵐康人
福島大学環境放射能研究所第9回成果報告会, 2023年02月, 福島大学環境放射能研究所
202302, 202302

リアルタイム浮遊菌カウンタによる微生物粒子の計測―一般大気中および林内における観測―　　　　　　　　　　　　　　　
渡辺幸一; 牧輝弥,保坂健太郎; 北和之
第14回大気バイオエアロゾルシンポジウム, 2023年01月, バイオエアロゾル研究会
202301, 202301

UV励起蛍光スペクトルによるバイオエアロゾルのカテゴリ別定量と 森林内でのバイオエア ロゾル濃度高度分布の観測　　　　　　　　　　　　　　　
北 和之、 南尾健太、 根内水紀、 井上未菜、 中川照喜、 高城有生、 反町篤行、 渡辺幸一、 保坂健太郎
第27回大気化学討論会, 2022年11月, 日本大気化学会
202211, 202211

蛍光を用いた放射性微粒子(CsMP) の検出可能性　　　　　　　　　　　　　　　
北和之、阿部善也、末木啓介、佐藤志彦、五十嵐康人
日本放射化学会第66回討論会, 2022年09月, 日本放射化学会
202209, 202209

フィルタサンプリングおよび蛍光スペクトル測定によるバイオエアロゾル定量法の開発　　　　　　　　　　　　　　　
北 和之、関口 碧、川上 花音、南尾健太、牧 輝弥、保坂健太郎、五十嵐康人
日本地球惑星科学連合2022年大会, 2022年05月, 公益社団法人日本地球惑星科学連合
202205, 202206

大気と植物・菌類間の放射性セシウム移行可能性の研究　　　　　　　　　　　　　　　
北和之・林奈穂・加納瑞季・五十嵐康人・保坂健太郎・古川純
放射能環境動態・影響評価ネットワーク共同利用・共同研究拠点2021年次報告会, 2022年02月, 放射能環境動態・影響評価ネットワーク
202202, 202202

植物園林内におけるリアルタイム浮遊菌カウンタによる微生物粒子の計測　　　　　　　　　　　　　　　
渡辺幸一、牧輝弥、保坂健太郎、北和之、五十嵐康人
第38回エアロゾル科学・技術研究討論会, 2021年08月, 日本アロゾル学会
202108, 202108

森林内外を浮遊するバイオエアロゾルの季節的変動の解明、森林内外を浮遊するバイオエアロゾルの季節的変動の解明　　　　　　　　　　　　　　　
牧輝弥、保坂健太郎、三星かおり、北和之、五十嵐康人
第38回エアロゾル科学・技術研究討論会, 2021年08月, 日本エアロゾル学会
202108, 202108

福島高セシウム沈着地域での事故後10年間の大気放射能濃度変化　　　　　　　　　　　　　　　
北和之、林奈穂、唐鵬、畑中恒太郎、木名瀬健、足立光司、財前祐二、石塚正秀、古川純、羽田野祐子、末木啓介、恩田裕一、二宮和彦、篠原厚、豊田栄、山田桂太、吉田尚弘、佐藤志彦、五十嵐康人
日本地球惑星科学連合2021年大会（JpGU Meeting 2021）, 2021年05月
202105, 202106

福島第一原発事故由来の放射性Cs 微粒子の蛍光特性　　　　　　　　　　　　　　　
阿部善也; 小野﨑晴佳; 石川真帆; 中井泉; 北和之; 五十嵐康人; 大浦泰嗣; 鶴田治雄; 森口祐一
日本放射化学会第64回討論会, 2020年09月
202009, 202009

降水で発生する生態学的セシウム再浮遊―粗大バイオエアロゾル　　　　　　　　　　　　　　　
五十嵐康人; 木名瀬健; 北和之; 林菜穂; 石塚正秀; 足立光司; 小板橋基夫; 関山剛; 恩田裕一
日本放射化学会第64回討論会, 2020年09月
202009, 202009

Re-suspension of insoluble Cs radioactive particles to the atmosphere　　　　　　　　　　　　　　　
Peng Tang; 畑中恒太郎; 北和之; 佐藤志彦; 二宮和彦; 篠原厚; 五十嵐康人
日本放射化学会第64回討論会, 2020年09月
202009, 202009

降水で誘発される生態学的セシウム再浮遊―バイオエアロゾル発生過程　　　　　　　　　　　　　　　
五十嵐康人; 木名瀬健; 足立光司; 関山剛; 北和之; 林菜穂; 石塚正秀; 小板橋基夫; 恩田裕一
第37回エアロゾル科学・技術研究討論会, 2020年08月, 日本エアロゾル学会, ［招待有り］
202008, 202008

Re-assessment of airborne radiocesium re-suspended from contaminated ground surface after the Fukushima Nuclear Accident
Kajino; M.; Watanabe; A.; Igarashi; Y.; Zaizen; Y.; Kinase; T.; Ishizuka; M.; Kita; K.
EGU General Assembly 2020, 2020年05月
202005, 202005

Rain-enhanced/induced bioecological resuspension of radiocaesium in a polluted forest in Fukushima
Igarashi; Y.; Kita; K.; Kinase; T.; Hayashi; N.; Ishizuka; M.; Adachi; K.; Koitabashi; M.; Onda; Y
EGU General Assembly 2020, 2020年05月
202005, 202005

福島帰宅困難地区で観測したセシウム-137大気放射能濃度の最近の変化　　　　　　　　　　　　　　　
北和之; 林菜穂; 木村茉央; 畑中恒太朗; 加納瑞樹; 南光太郎; Peng Tang; 古川純; 木名瀬健; 足立光司; 財前祐二; 濱賢三; 二宮和彦; 篠原厚; 佐藤志彦; 五十嵐康人
第21回「環境放射能」研究会, 2020年03月
202003, 202003

大気エアロゾルと植物・菌類間での放射性セシウム移行可能性の研究　　　　　　　　　　　　　　　
北和之、加納瑞季、二井矢航、木村茉央、古川純、羽田野祐子、五十嵐康人
2019年度放射能環境動態・影響評価ネットワーク共同研究拠点年次報告会, 2020年03月

Measurement of emission flux of radioactive cesium to the atmosphere　　　　　　　　　　　　　　　
Olivier MASSON; KITA Kazuyuki; Denis MARO; HARADA Koshi; HAYASHI Naho; MINAMI Kohtaro; HATANO Yuko; IGARASHI Yasuhito
2019年度放射能環境動態・影響評価ネットワーク共同研究拠点年次報告会, 2020年03月

筑波実験植物園におけるバイオエアロゾルとセシウム濃度の時系列データ解析　　　　　　　　　　　　　　　
石塚正秀; 田中邦明; 宮本えりか; 羽田野祐子; 保坂健太郎; 北和之; 牧輝也; 五十嵐康人
2019年度放射能環境動態・影響評価ネットワーク共同研究拠点年次報告会, 2020年03月

2019年7月の筑波実験植物園におけるきのこ胞子の放出観測　　　　　　　　　　　　　　　
石塚正秀、五十嵐康人、北和之、保坂健太郎、牧輝也、田中邦明、宮本えりか、羽田野祐子
第13回大気バイオエアロゾルシンポジウム, 2020年02月
202002, 202002

森林からのバイオエアロゾル放出フラックス推定の試み　　　　　　　　　　　　　　　
北 和之、南 光太郎、堅田元喜、反町篤行、原田晃司、林 奈穂、 保坂健太郎、牧輝弥、石塚正秀、渡辺幸一、羽田野祐子、五十嵐康人
第13回大気バイオエアロゾルシンポジウム, 2020年02月
202002, 202002

バイオエアロゾルにおける微生物群の遺伝学的特徴　　　　　　　　　　　　　　　
牧輝弥; 作田裕也; 河合慶; 藤田達之; 甲斐憲次; 北和之; 五十嵐康人; 保坂健太郎; 高見英人; 小林史尚; 黒崎泰典; 石塚正秀; 能田淳; 渡辺幸一; 洪天祥; 陳彬; 篠田雅人; 三星かおり; 西村隆; 岩坂泰信
第13回大気バイオエアロゾルシンポジウム, 2020年02月
202002, 202002

森林からのバイオエアロゾル放出フラックス推定とフィルタサンプリングされたバイオエアロゾル の蛍光測定の試み　　　　　　　　　　　　　　　
北和之; 林菜穂; 南光太郎; 木村茉央; 佐々 木完斉; 堅田元喜; 五十嵐康人; 反町篤行; 牧輝弥; 保坂健太郎; 古川純; 羽田野祐子; 池田; 遼; 足立光司; 財前祐二; 川端康弘; 大河内博; 河村公隆; 石塚正秀; 斎藤保典
第12回大気バイオエアロゾルシンポジウム, 2019年02月
202002, 202002

森林内を浮遊するバイオエアロゾルの群集構造変化　　　　　　　　　　　　　　　
牧輝弥; 北和之; 石塚正秀; 作田裕也; 保坂健太郎; 岩坂泰信; 五十嵐康人
第12回大気バイオエアロゾルシンポジウム, 2019年02月
202002, 202002

福島県内の里山地域における大気中Cs濃度の変遷　　　　　　　　　　　　　　　
五十嵐 康人,北 和之,木名瀬 健,林 奈穂,南 光太郎,木村 茉央,反町 篤行,大河内 博,後藤 友里絵,石塚 正秀,牧 輝弥; 保坂 健太郎,羽田野 祐子
第60回 大気環境学会年会, 2019年09月
201909, 201909

放射性セシウムの再飛散・再沈着モデリング　　　　　　　　　　　　　　　
梶野 瑞王,石塚 正秀,五十嵐 康人,北 和之,財前 祐二,木名瀨 健,渡邊 明
第60回 大気環境学会年会, 2019年09月
201909, 201909

緩和渦集積法を用いたバイオエアロゾルフラックスの測定　　　　　　　　　　　　　　　
反町篤行; 北和之; 南光太郎; 保坂健太郎; 堅田元喜; 五十嵐康人
第60回大気環境学会年会, 2019年09月
201909, 201909

多層陸面モデルを用いた真菌胞子の森林上空への乱流輸送過程の解析　　　　　　　　　　　　　　　
南光太郎; 堅田元喜; 北和之; 反町篤行; 保坂健太郎
第60回大気環境学会年会, 2019年09月
201909, 201909

筑波実験植物園におけるバイオエアロゾルとセシウム濃度の時系列データ解析　　　　　　　　　　　　　　　
石塚正秀、五十嵐康人、北和之、保坂健太郎、牧輝也、田中邦明、宮本えりか、羽田野祐子
放射能環境動態・影響評価ネットワーク共同研究拠点ERNCキックオフミーティング, 2019年07月

バイオエアロゾルによる放射性セシウム大気再飛散とそのフラックス推定の試み　　　　　　　　　　　　　　　
北 和之; 林 奈穂; 南 光太郎; 木村 茉央; 五十嵐 康人; 足立 光司; 牧 輝弥; 反町 篤行; 石塚 正秀; 古川 純; 二宮 和彦; 篠原 厚; Masson Olivier
日本地球惑星科学連合2019年大会, 2019年05月, ［招待有り］
201905, 201905

Bioaerosol emission and its role in re-emission of radioactive cesium from forest in Fukushima　　　　　　　　　　　　　　　
K. Kita; N. Hayashi; K. Minami; M. Kimura; Y. Igarashi; K. Adachi; T. Maki; M. Ishizuka; H. Okochi; J. Furukawa; K.Hosaka; K. Ninomiya and A.Shinohara
2018 joint 14th iCACGP Quadrennial Symposium/15th IGAC Science Conference（ 国際学会）, 2018年09月, ［招待有り］
201809, 201809

Bioaerosol emissions during the summer precipitation in Fukushima forest revealed by radiocesium observations　　　　　　　　　　　　　　　
N. Hayashi; K. Kita; Y. Igarashi; K. Adachi; T. Maki; and T. Kimura
2018 joint 14th iCACGP Quadrennial Symposium/15th IGAC Science Conference（ 国際学会）, 2018年09月, ［招待有り］
201809, 201809

緩和渦集積法を用いたバイオエアロゾル放出フラッ クスの測定システムの開発　　　　　　　　　　　　　　　
反町篤行; 北和之; 五十嵐康人; 保坂健太郎; 南光太郎; 堅田元喜; 羽田野裕子; 池田遼
第59回大気環境学会年会, 2018年09月
201809, 201809

降水時の森林からのバイオエアロゾル放出源変化　　　　　　　　　　　　　　　
林奈穂; 北和之; 五十嵐康人; 牧輝也; 小坂橋基夫
第35回エアロゾル科学・技術研究討論会, 2018年07月, 日本エアロゾル学会, ［招待有り］
201807, 201808

福島第一原発事故後の大気放射能に関する学会連携等による研究とその成果　　　　　　　　　　　　　　　
北和之
日本地球惑星科学連合2018年大会, 2018年05月, 公益社団法人日本地球惑星科学連合, ［招待有り］
201805, 201805

Increase of atmospheric concentration of radioactive cesium with bio-aerosols in a polluted area in Fukushima　　　　　　　　　　　　　　　
K. Kita; N. Hayashi; K. Minami; M. Kimura; Y. Igarashi; K. Adachi; T. Maki; M. Ishizuka; H. Okochi; J. Furukawa; K. Hosaka; K. Ninomiya and A. Shinohara
日本地球惑星科学連合2018年大会, 2018年05月, 公益社団法人日本地球惑星科学連合, ［招待有り］
201805, 201805

福島県浪江町の里山における大気エアロゾル中放射性セシウム濃度に及ぼす山林火災の影響　　　　　　　　　　　　　　　
吉岡颯,大河内博,張凱,勝見尚也,二宮和彦,北和之,五十嵐康人
日本地球惑星科学連合2018年大会, 2018年05月, 公益社団法人日本地球惑星科学連合, ［招待有り］
201805, 201805

2013年茨城県つくば市における大気Cs-137濃度変動とバイオエアロゾルによる寄与　　　　　　　　　　　　　　　
林奈穂, 北和之,五十嵐康人,足立 光司,木村 徹
日本地球惑星科学連合2018年大会, 2018年05月, 公益社団法人日本地球惑星科学連合, ［招待有り］
201805, 201805

シイタケ胞子の飛散機構の解明に向けた基礎的実験 -胞子の形状特性の観察　　　　　　　　　　　　　　　
石塚正秀; 田中邦明; 五十嵐康人; 保坂健太郎; 北 和之
日本地球惑星科学連合2018年大会, 2018年05月, 公益社団法人日本地球惑星科学連合, ［招待有り］
201805, 201805

シイタケ胞子の形状特性と胞子飛散に関する基礎的研究　　　　　　　　　　　　　　　
田中邦明; 石塚正秀; 五十嵐康人; 保坂健太郎; 北和之
平成３０年度土木学会四国支部第２４回技術研究発表会, 2018年05月, 公益社団法人 土木学会 四国支部, ［招待有り］
201805

Aerosol Emission from Forest by Precipitation: New Perspective for Atmosphere-Forest Interaction　　　　　　　　　　　　　　　
Yasuhito Igarashi; Naho Hayashi; Kazuyuki Kita; Teruya Maki; Yasunori Saito; Hiroshi Okochi; Kentaro Hosaka; Kouichi; Shiraishi; Takayuki Tomida; Kouji Adachi; Yuji Zaizen; Masahide Ishizuka and Atsuyuki Sorimachi
第11回大気バイオエアロゾルシンポジウム, 2018年02月
201802, 201802

福島山間部におけるバイオエアロゾルの放射性セシ ウム飛散における役割の推定　　　　　　　　　　　　　　　
北和之; 林奈穂; 南光太郎; 木村茉央; 五十嵐康人; 足立光司; 財前祐二; 牧輝弥; 保坂健太郎; 古川純; 大河内博; 石塚正秀; 反町篤行
第11回大気バイオエアロゾルシンポジウム, 2018年02月
201802, 201802

き の こ 胞子の 飛散機構の 解明に 向け た 基礎的実験　　　　　　　　　　　　　　　
石塚正秀; 田中邦明; 五十嵐康人; 保坂健太郎; 北和之
第11回大気バイオエアロゾルシンポジウム, 2018年02月
201802, 201802

Atmospheric re-suspension mechanism of radio-cesium - possibility of circulation between atmosphere and biosphere　　　　　　　　　　　　　　　
K. Kita; N. Hayashi; K. Minami; Y. Igarashi; K. Adachi; T. Maki; M. Ishiduka; H. Ohkochi; J. Furukawa; K. Ninomiya and A.Shinohara
2nd International Symposium of Quantum Beam Science at Ibaraki University, 2017年12月, 茨城大学大学院理工学研究科量子線科学専攻
201712, 201712

Bioaerosols sampled in Fukushima mountainous region and contribution to the radio-cesium resuspension　　　　　　　　　　　　　　　
K. Kita; N. Hayashi; K. Minami; M. Kimura; Y. Igarashi; K. Adachi; T. Maki; M. Ishiduka H. Ohkochi; J. Furukawa; K.; Ninomiya; and A. Shinohara
2017 Symposium on atmospheric chemistry and physics at mountain sites (ACPM2017)（ 国際学会）, 2017年11月, NPO法人富士山測候所を活用する会
201711, 201711

Temperate forest as big bioaerosol sources?: Implication from atmospheric Fukushima radiocesium studies　　　　　　　　　　　　　　　
Y. Igarashi; K. Kita; T. Maki; T. Kinase; N. Hayashi; K. Adachi; C. Takenaka; M. Kajino; M. Ishizuka; T. T. Sekiyama; Y.; Zaizen; K. Ninomiya; H. Okochi and A. Sorimachi
2017 Symposium on atmospheric chemistry and physics at mountain sites (ACPM2017)（ 国際学会）, 2017年11月, NPO法人富士山測候所を活用する会
201711, 201711

福島森林域でのバイオエアロゾルの観察-放射性セ シウムの大気再飛散担体の可能性　　　　　　　　　　　　　　　
林 奈穂; 北 和之; 五十嵐 康人; 足立 光司; 木村 徹; 牧 輝弥; 二宮 和彦; 篠原 厚; 豊田 栄; 石塚 正秀
第34回エアロゾル科学・技術研究討論会, 2017年08月, 日本エアロゾル学会, ［招待有り］
201708, 201708

日本地球惑星科学連合― 放射化学会連携による 福島第一原子力発電所近傍における事故5年後の 土壌中放射性物質の調査概要　　　　　　　　　　　　　　　
北 和之ほ か 41名
日本地球惑星科学連合-アメリカ地球物理学連合 ジョイントミーティング2017（国際学会）, 2017年05月, 公益社団法人日本地球惑星科学連合，米国地球物理学連合
201705, 201705

夏季-秋季における放射性セシウム大気再飛散のメ カニズム　　　　　　　　　　　　　　　
西岡 拓哉; 北 和之; 林 奈穂; 佐藤 武尊; 五十嵐 康人; 足立 光司; 財前 祐二; 豊田 栄; 山田 桂大; 吉田 尚弘; 牧 輝弥; 石塚 正; 秀; 二宮 和彦
日本地球惑星科学連合-アメリカ地球物理学連合 ジョイントミーティング2017（国際学会）, 2017年05月, 公益社団法人日本地球惑星科学連合，米国地球物理学連合
201705, 201705

Tropospheric ozone-enhanced layers observed over the equatorial Pacific Ocean and the contribution of transport of midlatitude UT/LS air　　　　　　　　　　　　　　　
Kazuyuki Kita; Hitomi Hayashi; S. Taguchi
American Geophysical Union 2007 Fall Meeting, 2007年12月, American Geophysical Union

2009年01月, 日本地球惑星科学連合

地球電磁気・地球惑星圏学会

日本気象学会

大気化学研究会

大気環境学会

American Geophysics Union

森林バイオエアロゾル放出動態解明と福島事故による放射性セシウム飛散の定量的推定
基盤研究(B)
茨城大学
2020年04月 - 2023年03月

森林バイオエアロゾルを標的とした高高度大気観測：風送拡散とその気候影響の評価
基盤研究(B)
2018年04月 - 2021年03月

福島第一原発事故で放出された放射性セシウムの大気再飛散と大気植生間の循環の解明
基盤研究(B)
茨城大学
2017年04月 - 2020年03月

降水によるエアロゾル発生現象：大気-森林相互作用の新展開
基盤研究(A)
2017年04月 - 2020年03月

冬季関東を巨大チャンバーに模した、ＣＣＮ生成過程に関する研究
基盤研究(B)
気象庁気象研究所
2015年04月 - 2020年03月

福島原発事故により放出された放射性核種の環境動態に関する学際的研究：総括班
新学術領域研究(研究領域提案型)
筑波大学
2012年06月 - 2017年03月

放射性物質の大気沈着・拡散過程および陸面相互作用の理解
新学術領域研究(研究領域提案型)
気象庁気象研究所
2012年06月 - 2017年03月

アジアのエアロゾル・雲・降水システムの観測・モデルによる統合的研究
基盤研究(S)
東京大学
2011年04月 - 2015年03月

可視紫外同時分光観測による地表境界層オゾンのリモートセンシング手法の開発
基盤研究(B)
茨城大学
2010年 - 2012年

超伝導サブミリ波リム放射サウンダ衛星観測にもとづく中層大気微量成分分布の解明
基盤研究(B)
京都大学
2010年 - 2012年

東アジアにおける炭素性エアロゾルの動態と直接放射効果
基盤研究(A)
東京大学
2008年 - 2010年

音響光学的手法による炭素質エアロゾルの放射特性の測定
基盤研究(B)
茨城大学
2006年 - 2009年

中国におけるブラックカーボンの粒径分布と混合状態の解明
基盤研究(B)
東京大学
2006年 - 2007年

PTR-MS測定法による大気中の揮発性有機化合物の動態解明
基盤研究(B)
東京大学
2003年 - 2005年

大気汚染と気候・降水・植生系間の大陸スケール相互作用に関する調査研究
基盤研究(C)
東京大学
2004年 - 2004年

大都市圏におけるオキシダントの光化学的制御戦略に関する研究
基盤研究(A)
東京大学
2002年 - 2004年

東南アジアのバイオマス燃焼による対流圏オゾン生成・増大の研究
基盤研究(B)
2001年 - 2004年

航空機搭載用一酸化炭素測定器の開発
基盤研究(A)
東京大学
2000年 - 2001年

成層圏・対流圏オゾン測定高精度化のための較正装置開発
基盤研究(C)
東京大学
1999年 - 2000年

対流圏光化学とオゾン収支
特定領域研究(A)
1998年 - 2000年

航空機観測による太平洋熱帯域の対流圏化学の研究:雨期における対流圏化学
基盤研究(B)
名古屋大学
1999年 - 1999年

インドネシア高層気象データベースの構築による赤道域準2年周期気候変動の解明
基盤研究(A)
神戸大学
1998年 - 1999年

インターネット系磁気圏監視システムのグローバル展開
国際学術研究
東京大学
1997年 - 1998年

太平洋赤道域の対流圈オゾン化学の研究
国際学術研究
名古屋大学
1997年 - 1998年

インドネシア海洋大陸における気候学的空白領域の補完
国際学術研究
京都大学
1996年 - 1997年

成層圏における窒素酸化物組成の夜間時間変化の観測
基盤研究(C)
東京大学
1996年 - 1997年

極域擾乱データの長期収集を目的としたインターネット系収録システムの開発
基盤研究(A)
東京大学
1995年 - 1997年

航空機観測による太平洋熱帯域の対流圏オゾン化学の研究
国際学術研究
名古屋大学
1996年 - 1996年

成層圏における窒素酸化物の夜間時間変化の研究
奨励研究(A)
東京大学
1995年 - 1995年

熱圏・電離圏における赤道異常の光学的研究
国際学術研究
東京大学
1993年 - 1995年

北極冠・カスプ・オーロラ帯の広域電磁・プラズマ擾乱の研究
国際学術研究
東京大学
1993年 - 1995年

対流圏光化学反応によるオゾンの生成と消失
一般研究(A)
東京大学
1992年 - 1994年

赤道異常における超高層大気素過程の光学的研究
国際学術研究
東京大学
1992年 - 1992年

成層圏メタン濃度の空間分布の連続測定
奨励研究(A)
東京大学
1991年 - 1991年

高速連続測定器による対流圏メタンの広域分布の研究
一般研究(A)
東京大学
1990年 - 1991年

特許4543186, 特願2009-295289, 二酸化窒素光分解コンバーターおよび二酸化窒素光分解コンバーターを備えた窒素酸化物濃度測定装置
北 和之