2023/10/02 更新

写真a

オオハタ ショウ
大畑 祥
OHATA Sho
所属
宇宙地球環境研究所 基盤研究部門 気象大気研究部 助教
大学院担当
大学院環境学研究科
職名
助教
連絡先
メールアドレス
外部リンク

学位 1

  1. 博士(理学) ( 2015年3月   東京大学 ) 

研究キーワード 2

  1. 大気化学

  2. エアロゾル

研究分野 1

  1. 環境・農学 / 環境動態解析  / エアロゾル、大気化学

現在の研究課題とSDGs 1

  1. エアロゾルの気候・環境影響

経歴 4

  1. 名古屋大学宇宙地球環境研究所   助教

    2018年10月 - 現在

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    国名:日本国

  2. 東京大学大学院理学系研究科   特任助教

    2018年5月 - 2018年9月

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    国名:日本国

  3. 東京大学大学院理学系研究科   特任研究員

    2015年4月 - 2018年4月

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    国名:日本国

  4. 日本学術振興会   特別研究員

    2012年4月 - 2015年3月

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    国名:日本国

学歴 3

  1. 東京大学   理学系研究科   地球惑星科学専攻

    2012年4月 - 2015年3月

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    国名: 日本国

  2. 東京大学   理学系研究科   地球惑星科学専攻

    2010年4月 - 2012年3月

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    国名: 日本国

  3. 東京大学   理学部

    2006年4月 - 2010年3月

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    国名: 日本国

受賞 3

  1. 日本気象学会 山本賞

    2017年10月   日本気象学会  

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    受賞区分:国内学会・会議・シンポジウム等の賞  受賞国:日本国

  2. 東京大学理学系研究科 研究奨励賞

    2015年3月   東京大学  

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    受賞国:日本国

  3. 日本地球惑星科学連合大会 学生優秀発表賞

    2014年5月   日本地球惑星科学連合大会  

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    受賞区分:国内学会・会議・シンポジウム等の賞  受賞国:日本国

 

論文 42

  1. A signature of aged biogenic compounds detected from airborne VOC measurements in the high arctic atmosphere in March/April 2018 査読有り 国際共著

    Holzinger Rupert, Eppers Oliver, Adachi Kouji, Bozem Heiko, Hartmann Markus, Herber Andreas, Koike Makoto, Millet Dylan B., Moteki Nobuhiro, Ohata Sho, Stratmann Frank, Yoshida Atsushi

    ATMOSPHERIC ENVIRONMENT   309 巻   頁: 119919 - 119919   2023年6月

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    掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.atmosenv.2023.119919

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  2. Evaluation of a method to quantify the number concentrations of submicron water-insoluble aerosol particles based on filter sampling and complex forward-scattering amplitude measurements 査読有り

    Ohata Sho, Moteki Nobuhiro, Kawanago Hikaru, Tobo Yutaka, Adachi Kouji, Mochida Michihiro

    AEROSOL SCIENCE AND TECHNOLOGY     頁: 1 - 22   2023年6月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Aerosol Science and Technology  

    Water-insoluble aerosol particles (WIAPs), such as black carbon (BC), mineral dust, and primary biological aerosol particles (PBAPs), affect climate through their interaction with radiation and clouds. However, with the exception of BC, methods to identify WIAP types and quantify their number concentrations are limited. Here, we evaluated a method that has been recently developed to measure the number concentrations of submicron WIAPs based on atmospheric aerosol measurements at an urban site in Nagoya, Japan. In this method, atmospheric aerosol particles are collected on a filter and dispersed in water. Then, the complex forward-scattering amplitudes of individual particles are measured. This complex parameter reflects the complex refractive index, volume, and shape of each measured particle, enabling the characterization of these physical properties from the signals. The WIAPs were classified as BC-like, dust-like, and PBAP-like particles based on their complex amplitude data. The number concentrations of BC-like particles were strongly correlated with those of refractory BC particles measured by a Single Particle Soot Photometer. BC-like and dust-like particles dominated the population of the submicron WIAPs, which was also confirmed using electron microscopy and Wideband Integrated Bioaerosol Sensor observations. Under the observed atmospheric conditions, the number concentrations of WIAPs were measured with their dispersion efficiency from a filter to water of approximately 50%. These results indicate that our method based on filter sampling and complex forward-scattering amplitude measurements has the potential to become a new technique for quantifying the spatio-temporal distributions of WIAPs.

    DOI: 10.1080/02786826.2023.2223387

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  3. The four-wavelength Photoacoustic Aerosol Absorption Spectrometer (PAAS-4 lambda) 査読有り

    Schnaiter Franz Martin, Linke Claudia, Asmi Eija, Servomaa Henri, Hyvarinen Antti-Pekka, Ohata Sho, Kondo Yutaka, Jarvinen Emma

    ATMOSPHERIC MEASUREMENT TECHNIQUES   16 巻 ( 11 ) 頁: 2753 - 2769   2023年6月

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    出版者・発行元:Atmospheric Measurement Techniques  

    In this paper, the Photoacoustic Aerosol Absorption Spectrometer (PAAS-4λ) is introduced. PAAS-4λ was specifically developed for long-term monitoring tasks in (unattended) air quality stations. It uses four wavelengths coupled to a single acoustic resonator in a compact and robust set-up. The instrument has been thoroughly characterized and carefully calibrated in the laboratory using NO2/air mixtures and Nigrosin aerosol. It has an ultimate 1σ detection limit below 0.1 Mm-1, at a measurement precision and accuracy of 3 % and 10 %, respectively. In order to demonstrate the PAAS-4λ suitability for long-term monitoring tasks, the instrument is currently validated at the air quality monitoring station Pallas in Finland, about 140 km north of the Arctic circle. A total of 11 months of PAAS-4λ data from this deployment are presented and discussed in terms of instrument performance. Intercomparisons with the filter-based photometers of a continuous soot monitoring system (COSMOS), the Multi-Angle Absorption Photometer (MAAP), and Aethalometer (AE33) demonstrate the capabilities and value of PAAS-4λ, as well as for the validation of the widely used filter-based instruments. Copyright:

    DOI: 10.5194/amt-16-2753-2023

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  4. Physical and chemical properties of PM1 in Delhi: A comparison between clean and polluted days 査読有り

    Malik Arpit, Aggarwal Shankar G., Kunwar Bhagawati, Deshmukh Dhananjay Kumar, Shukla Kritika, Agarwal Rishu, Singh Khem, Soni Daya, Sinha Puna Ram, Ohata Sho, Mori Tatsuhiro, Koike Makoto, Kawamura Kimitaka, Kondo Yutaka

    SCIENCE OF THE TOTAL ENVIRONMENT   892 巻   頁: 164266 - 164266   2023年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Science of the Total Environment  

    Considering the significance of PM1 aerosol in assessing health impacts of air pollution, an extensive analysis of PM1 samples collected at an urban site in Delhi is presented in this study. Overall, PM1 contributed to about 50 % of PM2.5 mass which is alarming especially in Delhi where particle mass loadings are usually higher than prescribed limits. Major portion of PM1 consisted of organic matter (OM) that formed nearly 47 % of PM1 mass. Elemental carbon (EC) contributed to about 13 % of PM1 mass, whereas SO42− (16 %), NH4+ (10 %), NO3− (4 %) and Cl− (3 %) were the major inorganic ions present. Sampling was performed in two distinctive campaign periods (in terms of meteorological conditions and heating (fire) activities), during the year 2019, each spanning two-week time, i.e. (i) September 3rd-16th (clean days), and (ii) November 22nd-December 5th (polluted days). Additionally, PM2.5 and black carbon (BC) were measured simultaneously for subsequent analysis. The 24-h averaged mean concentrations of PM2.5 and BC during clean days (polluted days) were 70.6 ± 26.9 and 3.9 ± 1.0 μg m−3 (196 ± 104 and 7.6 ± 4.1 μg m−3), respectively, which were systematically lower (higher) than that of the annual mean (taken from studies conducted at same site in 2019) of 142 and 5.7 μg m−3, respectively. Changes in characteristic ratios (i.e., organic carbon (OC)/elemental carbon (EC) and K+/EC) of chemical species detected in PM1 show an increase in biomass emissions during polluted days. Increase in biomass emission can be attributed to increase in heating practices (burning of biofuels such as wood logs, straw, and cow-dung cake) in- and around- Delhi because of fall in temperature during second campaign. Furthermore, a significant increase in NO3− fraction of PM1 is observed during second campaign which shows fog processing of NOX due to conducive meteorological conditions in winters. Also, comparatively stronger correlation of NO3− with K+ during second campaign (r = 0.98 as compared to r = 0.5 during first campaign) suggests the increased heating practices to be a contributing factor for increased fraction of NO3− in PM1. We observed that during polluted days, meteorological parameters such as dispersion rate also played a major role in intensifying the impact of increased local emissions due to heating activities. Apart from this, change in the direction of regional emission transport to study site and the topology of Delhi are the possible reasons for the elevated pollution level, especially PM1 during winter in Delhi. This study also suggests that black carbon measurement techniques used in current study (optical absorbance with heated inlet and evolved carbon techniques) can be used as reference techniques to determine the site-specific calibration constant of optical photometers for urban aerosol.

    DOI: 10.1016/j.scitotenv.2023.164266

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  5. Constraining the complex refractive index of black carbon particles using the complex forward-scattering amplitude 査読有り

    Moteki Nobuhiro, Ohata Sho, Yoshida Atsushi, Adachi Kouji

    AEROSOL SCIENCE AND TECHNOLOGY   57 巻 ( 7 ) 頁: 678 - 699   2023年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Aerosol Science and Technology  

    Black carbon is the largest contributor to global aerosol’s shortwave absorption in the current atmosphere and is an important positive climate forcer. The complex refractive index, m = m r + im i, the primary determinant of the absorbed and scattered energies of incident radiation per unit volume of particulate material, has not been accurately known for atmospheric black carbon material. An accurate value at visible wavelengths has been difficult to obtain due to the black carbon’s wavelength-scale irregularity and variability of aggregate shape, distribution in particle size, and mixing with other aerosol compounds. Here, we present a method to constrain a plausible (m r, m i) domain for black carbon from the observed distribution of the complex forward-scattering amplitude S(0°). This approach suppresses the biases due to the above-mentioned complexities. The S(0°) distribution of black carbon is acquired by performing single particle S(0°) measurements in a water medium after collecting atmospheric aerosols into water. We demonstrate the method operating at λ = 0.633 μm for constraining the refractive index of black carbon aerosols in the north-western Pacific boundary layer. From the plausible (m r, m i) domain consistent with the observed S(0°) distributions and the reported range of mass absorption cross-section, we conservatively select 1.95 + 0.96i as a recommendable value of the refractive index for uncoated black carbon at visible wavelengths. The recommendable value is 0.17 larger in m i than the widely used value 1.95 + 0.79i in current aerosol-climate models, implying a ∼16% underestimate of shortwave absorption by black carbon aerosols in current climate simulations.

    DOI: 10.1080/02786826.2023.2202243

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  6. エアロゾル-放射・雲相互作用 査読有り

    松井仁志, 大畑祥, 當房豊, 松木篤, 板橋秀一, 大島長, 鈴木健太郎, 佐藤陽祐

    大気化学研究   48 巻   頁: 048A01   2023年1月

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  7. Measurement of number and mass size distributions of light-absorbing iron oxide aerosols in liquid water with a modified single-particle soot photometer 査読有り

    Mori Tatsuhiro, Kondo Yutaka, Goto-Azuma Kumiko, Moteki Nobuhiro, Yoshida Atsushi, Fukuda Kaori, Ogawa-Tsukagawa Yoshimi, Ohata Sho, Koike Makoto

    AEROSOL SCIENCE AND TECHNOLOGY   57 巻 ( 1 ) 頁: 35 - 49   2022年12月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Aerosol Science and Technology  

    Here, we used a modified single-particle soot photometer (SP2) coupled with a concentric pneumatic nebulizer to measure the size-resolved number and mass concentrations of light-absorbing iron oxide aerosols (FeOx) in liquid water (C NFeOx and C MFeOx, respectively). The SP2 could selectively detect individual FeOx particles in mixed wüstite–fullerene soot laboratory samples and melted Arctic snow samples. The nebulizer efficiency for FeOx particles was about 50% within the 70–650 nm diameter range, as derived from the ratio of the volume of ammonium sulfate before and after extraction by the nebulizer and the size-resolved transmission efficiency in the nebulizer–SP2 sampling line. Uncertainty from the boundary lines empirically drawn to discriminate the scatterplots of FeOx and black carbon in the mixed wüstite–fullerene soot suspensions and snow samples was approximately 3.0% and 10%, respectively. Overall uncertainty in total C NFeOx and C MFeOx (220–1400 nm) was approximately 19% and 18%, respectively. After storage at 4 °C for 16 months, the FeOx particle size distributions in melted Arctic snow had remained stable, and C NFeOx and C MFeOx had changed by less than 19% and 1.0%, on average, respectively. Most of the FeOx on dust particles measured by this system was estimated to be in the diameter range smaller than 1000 nm, considering the nebulizer efficiency for dust particles. The high accuracy of the C NFeOx and C MFeOx measurements will help to improve our quantitative understanding of the wet deposition of FeOx and provide more accurate estimates of the effects of FeOx on snow surface albedo.

    DOI: 10.1080/02786826.2022.2144113

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  8. The Ny-Ålesund Aerosol Cloud Experiment (NASCENT): Overview and First Results 査読有り 国際共著

    J. T. Pasquier;R. O. David;G. Freitas;R. Gierens;Y. Gramlich;S. Haslett;G. Li;B. Schäfer;K. Siegel;J. Wieder;K. Adachi;F. Belosi;T. Carlsen;S. Decesari;K. Ebell;S. Gilardoni;M. Gysel-Beer;J. Henneberger;J. Inoue;Z. A. Kanji;M. Koike;Y. Kondo;R. Krejci;U. Lohmann;M. Maturilli;M. Mazzolla;R. Modini;C. Mohr;G. Motos;A. Nenes;A. Nicosia;S. Ohata;M. Paglione;S. Park;R. E. Pileci;F. Ramelli;M. Rinaldi;C. Ritter;K. Sato;T. Storelvmo;Y. Tobo;R. Traversi;A. Viola;P. Zieger

    Bulletin of the American Meteorological Society     2022年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1175/bams-d-21-0034.1

  9. Contrasting source contributions of Arctic black carbon to atmospheric concentrations, deposition flux, and atmospheric and snow radiative effects 査読有り

    Matsui Hitoshi, Mori Tatsuhiro, Ohata Sho, Moteki Nobuhiro, Oshima Naga, Goto-Azuma Kumiko, Koike Makoto, Kondo Yutaka

    ATMOSPHERIC CHEMISTRY AND PHYSICS   22 巻 ( 13 ) 頁: 8989 - 9009   2022年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Atmospheric Chemistry and Physics  

    Black carbon (BC) particles in the Arctic contribute to rapid warming of the Arctic by heating the atmosphere and snow and ice surfaces. Understanding the source contributions to Arctic BC is therefore important, but they are not well understood, especially those for atmospheric and snow radiative effects. Here we estimate simultaneously the source contributions of Arctic BC to near-surface and vertically integrated atmospheric BC mass concentrations (MBC-SRF and MBC-COL), BC deposition flux (MBC-DEP), and BC radiative effects at the top of the atmosphere and snow surface (REBC-TOA and REBC-SNOW) and show that the source contributions to these five variables are highly different. In our estimates, Siberia makes the largest contribution to MBC-SRF, MBC-DEP, and REBC-SNOW in the Arctic (defined as >70° N), accounting for 70 %, 53 %, and 41 %, respectively. In contrast, Asia's contributions to MBC-COL and REBC-TOA are largest, accounting for 37 % and 43 %, respectively. In addition, the contributions of biomass burning sources are larger (29 %-35 %) to MBC-DEP, REBC-TOA, and REBC-SNOW, which are highest from late spring to summer, and smaller (5.9 %-17 %) to MBC-SRF and MBC-COL, whose concentrations are highest from winter to spring. These differences in source contributions to these five variables are due to seasonal variations in BC emission, transport, and removal processes and solar radiation, as well as to differences in radiative effect efficiency (radiative effect per unit BC mass) among sources. Radiative effect efficiency varies by a factor of up to 4 among sources (1471-5326 W g-1) depending on lifetimes, mixing states, and heights of BC and seasonal variations of emissions and solar radiation. As a result, source contributions to radiative effects and mass concentrations (i.e., REBC-TOA and MBC-COL, respectively) are substantially different. The results of this study demonstrate the importance of considering differences in the source contributions of Arctic BC among mass concentrations, deposition, and atmospheric and snow radiative effects for accurate understanding of Arctic BC and its climate impacts.

    DOI: 10.5194/acp-22-8989-2022

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  10. Measurement of Black Carbon in Delhi: Evidences of Regional Transport, Meteorology and Local Sources for Pollution Episodes 査読有り 国際共著

    Malik Arpit, Aggarwal Shankar G., Ohata Sho, Mori Tatsuhiro, Kondo Yutaka, Sinha Puna Ram, Patel Prashant, Kumar Baban, Singh Khem, Soni Daya, Koike Makoto

    AEROSOL AND AIR QUALITY RESEARCH   22 巻 ( 8 )   2022年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Aerosol and Air Quality Research  

    Measurement of particulate matter (PM) constituent such as black carbon (BC) over urban sites is critically important owing to its adverse health and climate impacts. However, the impacts associated with BC are poorly understood primarily because of the scarcity and uncertainties of measurements of BC. Here, we present BC measurement at an urban site of Delhi using a characterized continuous soot monitoring system (COSMOS) for a year-long period, i.e., from September, 2019 to August, 2020. This measurement period covers events, i.e., period of crop residue burnings from nearby states, festive events, e.g., Diwali and New Year, and first COVID-19 lockdown period. Effects of these events combining with local emissions and meteorological conditions on BC mass concentration (MBC) are investigated to find the possible cause of severe pollution levels in Delhi. Mean MBC for the complete observation period was found to be 5.02 ± 4.40 µg m–3. MBC showed significant seasonal as well diurnal variations. Winter season (December to February) is observed to be the most polluted season owing to increased local emissions and non-favorable meteorological conditions. Regional emission from crop burning in nearby states during October and November is the main contributing factor for increased pollution in this post-monsoon season. Furthermore, analysis reveals that cracker burning during festivals can also be considered as contributing factor to high MBC for a short period in post-monsoon and winter seasons. Significant decrease in MBC due to COVID-19 lockdown is also observed. MBC in summer and monsoon are lower as compared to other seasons but are still higher than mean MBC levels in several other urban cities of different countries. Also, the BC data obtained from nearby sites and Modern-Era Retrospective analysis for Research and Applications-version 2 (MERRA-2)’s surface black carbon (SBC) are compared against the MBC to evaluate coherency among the different datasets, and discussed in detail.

    DOI: 10.4209/aaqr.220128

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  11. Offline analysis of the chemical composition and hygroscopicity of submicrometer aerosol at an Asian outflow receptor site and comparison with online measurements 査読有り 国際共著

    Deng Yange, Fujinari Hiroaki, Yai Hikari, Shimada Kojiro, Miyazaki Yuzo, Tachibana Eri, Deshmukh Dhananjay K., Kawamura Kimitaka, Nakayama Tomoki, Tatsuta Shiori, Cai Mingfu, Xu Hanbing, Li Fei, Tan Haobo, Ohata Sho, Kondo Yutaka, Takami Akinori, Hatakeyama Shiro, Mochida Michihiro

    ATMOSPHERIC CHEMISTRY AND PHYSICS   22 巻 ( 8 ) 頁: 5515 - 5533   2022年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Atmospheric Chemistry and Physics  

    Filter-based offline analysis of atmospheric aerosol hygroscopicity coupled to composition analysis provides information complementary to that obtained from online analysis. However, its application itself and comparison to online analysis have remained limited to date. In this study, daily submicrometer aerosol particles (PM0.95, 50% cutoff diameter 0.95μm) were collected onto quartz fiber filters on Okinawa Island, a receptor of East Asian outflow, in the autumn of 2015. The chemical composition of water-soluble matter (WSM) in PM0.95, PM0.95 itself, and their respective hygroscopicities were characterized through the offline use of an aerosol mass spectrometer and a hygroscopicity tandem differential mobility analyzer. Thereafter, results were compared with those obtained from online analyses. Sulfate dominated the WSM mass (59%), followed by water-soluble organic matter (WSOM, 20%) and ammonium (13%). WSOM accounted for most (91%) of the mass of extracted organic matter (EOM) and the atomic O-to-C ratios (O:C) of WSOM and EOM were high (mean±standard deviation were 0.84±0.08 and 0.78±0.08, respectively), both of which indicate highly aged characteristics of the observed aerosol. The hygroscopic growth curves showed clear hysteresis for most samples. At 85% relative humidity (RH), the calculated hygroscopicity parameter κ values of the WSM (κWSM), WSOM, EOM, and PM0.95 (κPM0.95) were 0.50±0.03, 0.22±0.12, 0.20±0.11, and 0.47±0.03, respectively. An analysis using the thermodynamic Extended Aerosol Inorganics Model (E-AIM) shows, on average, that inorganic salts and WSOM contributed 88% and 12%, respectively, of the κWSM (or κPM0.95). High similarities were found between offline and online analysis for chemical compositions that are related to particle hygroscopicity (the mass fractions and O:C of organics and the degree of neutralization) and also for aerosol hygroscopicity. As possible factors governing the variation in κWSM, the influences of WSOM abundance and the neutralization of inorganic salts were assessed. At high RH (70%-90%), the hygroscopicity of WSM and PM0.95 was affected considerably by the presence of organic components; at low RH (20%-50%), the degree of neutralization could be important. This study not only characterized aerosol hygroscopicity at the receptor site of East Asian outflow but also shows that offline hygroscopicity analysis is an appropriate method, at least for aerosols of the studied type. The results encourage further applications to other environments and to more in-depth hygroscopicity analysis, in particular for organic fractions.

    DOI: 10.5194/acp-22-5515-2022

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  12. Arctic black carbon during PAMARCMiP 2018 and previous aircraft experiments in spring 査読有り 国際共著

    Ohata Sho, Koike Makoto, Yoshida Atsushi, Moteki Nobuhiro, Adachi Kouji, Oshima Naga, Matsui Hitoshi, Eppers Oliver, Bozem Heiko, Zanatta Marco, Herber Andreas B.

    ATMOSPHERIC CHEMISTRY AND PHYSICS   21 巻 ( 20 ) 頁: 15861 - 15881   2021年11月

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    担当区分:筆頭著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Atmospheric Chemistry and Physics  

    Vertical profiles of the mass concentration of black carbon (BC) were measured at altitudes up to 5 km during the PAMARCMiP (Polar Airborne Measurements and Arctic Regional Climate Model simulation Project) aircraft-based field experiment conducted around the northern Greenland Sea (Fram Strait) during March and April 2018 from operation base Station Nord (81.6'N, 16.7'W). Median BC mass concentrations in individual altitude ranges were 7-18 ng m-3 at standard temperature and pressure at altitudes below 4.5 km. These concentrations were systematically lower than previous observations in the Arctic in spring, conducted by ARCTAS-A in 2008 and NETCARE in 2015, and similar to those observed during HIPPO3 in 2010. Column amounts of BC for altitudes below 5 km in the Arctic (>66.5'N; COLBC), observed during the ARCTAS-A and NETCARE experiments, were higher by factors of 4.2 and 2.7, respectively, than those of the PAMARCMiP experiment. These differences could not be explained solely by the different locations of the experiments. The year-to-year variation of COLBC values generally corresponded to that of biomass burning activities in northern midlatitudes over western and eastern Eurasia. Furthermore, numerical model simulations estimated the year-to-year variation of contributions from anthropogenic sources to be smaller than 30 %-40 %. These results suggest that the year-to-year variation of biomass burning activities likely affected BC amounts in the Arctic troposphere in spring, at least in the years examined in this study. The year-to-year variations in BC mass concentrations were also observed at the surface at high Arctic sites Ny-Ålesund and Utqiävik (formerly known as Barrow, the location of Barrow Atmospheric Baseline Observatory), although their magnitudes were slightly lower than those in COLBC. Numerical model simulations in general successfully reproduced the observed COLBC values for PAMARCMiP and HIPPO3 (within a factor of 2), whereas they markedly underestimated the values for ARCTAS-A and NETCARE by factors of 3.7-5.8 and 3.3-5.0, respectively. Because anthropogenic contributions account for nearly all of the COLBC (82 %-98 %) in PAMARCMiP and HIPPO3, the good agreement between the observations and calculations for these two experiments suggests that anthropogenic contributions were generally well reproduced. However, the significant underestimations of COLBC for ARCTAS-A and NETCARE suggest that biomass burning contributions were underestimated. In this study, we also investigated plumes with enhanced BC mass concentrations, which were affected by biomass burning emissions, observed at 5 km altitude. Interestingly, the mass-averaged diameter of BC (core) and the shell-to-core diameter ratio of BC-containing particles in the plumes were generally not very different from those in other air samples, which were considered to be mostly aged anthropogenic BC. These observations provide a useful basis to evaluate numerical model simulations of the BC radiative effect in the Arctic region in spring.

    DOI: 10.5194/acp-21-15861-2021

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  13. Estimates of mass absorption cross sections of black carbon for filter-based absorption photometers in the Arctic 査読有り 国際共著

    Ohata Sho, Mori Tatsuhiro, Kondo Yutaka, Sharma Sangeeta, Hyvarinen Antti, Andrews Elisabeth, Tunved Peter, Asmi Eija, Backman John, Servomaa Henri, Veber Daniel, Koike Makoto, Kanaya Yugo, Yoshida Atsushi, Moteki Nobuhiro, Zhao Yongjing, Matsushita Junji, Oshima Naga, Eleftheriadis Konstantinos, Vratolis Stergios, Krejci Radovan, Zieger Paul, Tobo Yutaka

    ATMOSPHERIC MEASUREMENT TECHNIQUES   14 巻 ( 10 ) 頁: 6723 - 6748   2021年10月

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    担当区分:筆頭著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Atmospheric Measurement Techniques  

    Long-Term measurements of atmospheric mass concentrations of black carbon (BC) are needed to investigate changes in its emission, transport, and deposition. However, depending on instrumentation, parameters related to BC such as aerosol absorption coefficient (babs) have been measured instead. Most ground-based measurements of babs in the Arctic have been made by filter-based absorption photometers, including particle soot absorption photometers (PSAPs), continuous light absorption photometers (CLAPs), Aethalometers, and multi-Angle absorption photometers (MAAPs). The measured babs can be converted to mass concentrations of BC (MBC) by assuming the value of the mass absorption cross section (MAC; MBCCombining double low lineg babs/g MAC). However, the accuracy of conversion of babs to MBC has not been adequately assessed. Here, we introduce a systematic method for deriving MAC values from babs measured by these instruments and independently measured MBC. In this method, MBC was measured with a filter-based absorption photometer with a heated inlet (COSMOS). COSMOS-derived MBC (MBC (COSMOS)) is traceable to a rigorously calibrated single particle soot photometer (SP2), and the absolute accuracy of MBC (COSMOS) has been demonstrated previously to be about 15g % in Asia and the Arctic. The necessary conditions for application of this method are a high correlation of the measured babs with independently measured MBC and long-Term stability of the regression slope, which is denoted as MACcor (MAC derived from the correlation). In general, babs-MBC (COSMOS) correlations were high (r2Combining double low lineg 0.76-0.95 for hourly data) at Alert in Canada, Ny-Ålesund in Svalbard, Barrow (NOAA Barrow Observatory) in Alaska, Pallastunturi in Finland, and Fukue in Japan and stable for up to 10 years. We successfully estimated MACcor values (10.8-15.1g m2g g-1 at a wavelength of 550g nm for hourly data) for these instruments, and these MACcor values can be used to obtain error-constrained estimates of MBC from babs measured at these sites even in the past, when COSMOS measurements were not made. Because the absolute values of MBC at these Arctic sites estimated by this method are consistent with each other, they are applicable to the study of spatial and temporal variation in MBC in the Arctic and to evaluation of the performance of numerical model calculations.

    DOI: 10.5194/amt-14-6723-2021

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  14. Absorption instruments inter-comparison campaign at the Arctic Pallas station 査読有り 国際共著

    Asmi Eija, Backman John, Servomaa Henri, Virkkula Aki, Gini Maria I, Eleftheriadis Konstantinos, Mueller Thomas, Ohata Sho, Kondo Yutaka, Hyvarinen Antti

    ATMOSPHERIC MEASUREMENT TECHNIQUES   14 巻 ( 8 ) 頁: 5397 - 5413   2021年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Atmospheric Measurement Techniques  

    Aerosol light absorption was measured during a 1-month field campaign in June-July 2019 at the Pallas Global Atmospheric Watch (GAW) station in northern Finland. Very low aerosol concentrations prevailed during the campaign, which posed a challenge for the instruments' detection capabilities. The campaign provided a real-world test for different absorption measurement techniques supporting the goals of the European Metrology Programme for Innovation and Research (EMPIR) Black Carbon (BC) project in developing aerosol absorption standard and reference methods. In this study we compare the results from five filter-based absorption techniques - aethalometer models AE31 and AE33, a particle soot absorption photometer (PSAP), a multi-angle absorption photometer (MAAP), and a continuous soot monitoring system (COSMOS) - and from one indirect technique called extinction minus scattering (EMS). The ability of the filter-based techniques was shown to be adequate to measure aerosol light absorption coefficients down to around 0.01g¯Mm-1 levels when data were averaged to 1-2g¯h. The hourly averaged atmospheric absorption measured by the reference MAAP was 0.09g¯Mm-1 (at a wavelength of 637g¯nm). When data were averaged for >1g¯h, the filter-based methods agreed to around 40g¯%. COSMOS systematically measured the lowest absorption coefficient values, which was expected due to the sample pre-treatment in the COSMOS inlet. PSAP showed the best linear correlation with MAAP (slopeCombining double low line0.95, R2Combining double low line0.78), followed by AE31 (slopeCombining double low line0.93). A scattering correction applied to PSAP data improved the data accuracy despite the added noise. However, at very high scattering values the correction led to an underestimation of the absorption. The AE31 data had the highest noise and the correlation with MAAP was the lowest (R2Combining double low line0.65). Statistically the best linear correlations with MAAP were obtained for AE33 and COSMOS (R2 close to 1), but the biases at around the zero values led to slopes clearly below 1. The sample pre-treatment in the COSMOS instrument resulted in the lowest fitted slope. In contrast to the filter-based techniques, the indirect EMS method was not adequate to measure the low absorption values found at the Pallas site. The lowest absorption at which the EMS signal could be distinguished from the noise was >0.1g¯Mm-1 at 1-2g¯h averaging times. The mass absorption cross section (MAC) value measured at a range 0-0.3g¯Mm-1 was calculated using the MAAP and a single particle soot photometer (SP2), resulting in a MAC value of 16.0±5.7g¯m2g-1. Overall, our results demonstrate the challenges encountered in the aerosol absorption measurements in pristine environments and provide some useful guidelines for instrument selection and measurement practices. We highlight the need for a calibrated transfer standard for better inter-comparability of the absorption results.

    DOI: 10.5194/amt-14-5397-2021

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  15. Seasonal Variation of Wet Deposition of Black Carbon at Ny-angstrom lesund, Svalbard 査読有り 国際共著

    Mori Tatsuhiro, Kondo Yutaka, Ohata Sho, Goto-Azuma Kumiko, Fukuda Kaori, Ogawa-Tsukagawa Yoshimi, Moteki Nobuhiro, Yoshida Atsushi, Koike Makoto, Sinha P. R., Oshima Naga, Matsui Hitoshi, Tobo Yutaka, Yabuki Masanori, Aas Wenche

    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES   126 巻 ( 12 )   2021年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Atmospheres  

    Black carbon (BC) aerosol deposited in and onto Arctic snow increases the snow's absorption of solar radiation and accelerates snowmelt. Concentrations of BC in the Arctic atmosphere and snow are controlled by wet deposition; however, details of this process are poorly understood owing to the scarcity of time-resolved measurements of BC in hydrometeors. We measured mass concentrations of BC in hydrometeors (CMBC) and in air (MBC) with 16% and 15% accuracies, respectively, at Ny-Ålesund, Svalbard during 2012–2019. Median monthly MBC and CMBC values showed similar seasonal variations, being high in winter-spring and low in summer. Median monthly BC wet deposition mass flux (FMBC) was highest in winter and lowest in summer, associated with seasonal patterns of CMBC and precipitation. Seasonally averaged BC size distributions in hydrometeors were similar except for summer. Measurements of MBC and CMBC in spring 2017 showed a size-independent removal efficiency, indicating that BC-containing particles were efficiently activated into cloud droplets. These observations at Ny-Ålesund were compared with observations at Barrow, Alaska, during 2013–2017. The near-surface MBC at Ny-Ålesund and Barrow had similar seasonal patterns; however, the two sites differed in CMBC and FMBC. In summer, CMBC was low at Ny-Ålesund but moderate at Barrow, likely reflecting differences in MBC in the lower troposphere. Seasonally averaged BC size distributions in hydrometeors were similar at both sites, suggesting that average BC size distributions are similar in the Arctic lower troposphere. The efficiency of BC removal tends to be size-independent during transport, leading to the observed similarity.

    DOI: 10.1029/2020JD034110

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    その他リンク: https://onlinelibrary.wiley.com/doi/full-xml/10.1029/2020JD034110

  16. Compositions and mixing states of aerosol particles by aircraft observations in the Arctic springtime, 2018 査読有り

    Adachi Kouji, Oshima Naga, Ohata Sho, Yoshida Atsushi, Moteki Nobuhiro, Koike Makoto

    ATMOSPHERIC CHEMISTRY AND PHYSICS   21 巻 ( 5 ) 頁: 3607 - 3626   2021年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Atmospheric Chemistry and Physics  

    Aerosol particles were collected at various altitudes in the Arctic during the Polar Airborne Measurements and Arctic Regional Climate Model Simulation Project 2018 (PAMARCMiP 2018) conducted in the early spring of 2018. The composition, size, number fraction, and mixing state of individual aerosol particles were analyzed using transmission electron microscopy (TEM), and their sources and transport were evaluated by numerical model simulations. We found that sulfate, sea-salt, mineral-dust, K-bearing, and carbonaceous particles were the major aerosol constituents. Many particles were composed of two or more compositions that had coagulated and were coated with sulfate, organic materials, or both. The number fraction of mineral-dust and sea-salt particles decreased with increasing altitude. The K-bearing particles increased within a biomass burning (BB) plume at altitudes > 3900 m, which originated from Siberia. Chlorine in sea-salt particles was replaced with sulfate at high altitudes. These results suggest that the sources, transport, and aging of Arctic aerosols largely vary depending on the altitude and air-mass history. We also provide the occurrences of solid-particle inclusions (soot, fly-ash, and Fe-aggregate particles), some of which are light-absorbing particles. They were mainly emitted from anthropogenic and biomass burning sources and were embedded within other relatively large host particles. Our TEM measurements revealed the detailed mixing state of individual particles at various altitudes in the Arctic. This information facilitates the accurate evaluation of the aerosol influences on Arctic haze, radiation balance, cloud formation, and snow/ice albedo when deposited.

    DOI: 10.5194/acp-21-3607-2021

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  17. Studies on Arctic aerosols and clouds during the ArCS project 査読有り

    Koike M., Goto-Azuma K., Kondo Y., Matsui H., Mori T., Moteki N., Ohata S., Okamoto H., Oshima N., Sato K., Takano T., Tobo Y., Ukita J., Yoshida A.

    POLAR SCIENCE   27 巻   頁: 100621 - 100621   2021年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Polar Science  

    Aerosols and clouds play important roles in the Arctic climate. Conversely, aerosol emissions and cloud formation are affected by changes in the Arctic climate. This paper reviews studies of aerosols and clouds performed during the Arctic Challenge for Sustainability (ArCS) project carried out by the National Institute of Polar Research (NIPR) in Japan and collaborating institutions. The ArCS project included intensive studies of black carbon aerosols (BC). We installed Continuous Soot Monitoring System (COSMOS) instruments to measure atmospheric BC at four locations in the Arctic, establishing the Arctic BC COSMOS Measurement Network (ABCM-net). We also measured BC concentrations in snowpack in extensive areas of the Arctic and showed that previous studies have greatly overestimated BC in snowpack. We developed and improved new aerosol models that achieved better agreements with measurements of BC in the Arctic atmosphere, snowpack, and falling snow. We made new estimates of radiative forcing of BC in the Arctic atmosphere and snow/ice surfaces that lower their albedo. In addition to these researches on BC, we made accurate measurements of ice nucleating particles (INPs) at Ny-Ålesund, Svalbard, showing that their concentrations increased in summer as a result of dust particle emissions from glacial outwash sediments. This high ice nucleating ability was likely due to the presence of organic substances mixed with the dust particles. We also made continuous cloud radar measurements and the first continuous in-situ measurements of cloud microphysical properties in the Arctic at Ny-Ålesund. Results from these cloud measurements and their relationship with aerosols are described.

    DOI: 10.1016/j.polar.2020.100621

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  18. Seasonal Variation of Wet Deposition of Black Carbon in Arctic Alaska 査読有り 国際共著

    T. Mori, Y. Kondo, S. Ohata, Y. Zhao, P. R. Sinha, N. Oshima, H. Matsui, N. Moteki, M. Koike

    Journal of Geophysical Research: Atmospheres   125 巻 ( 16 )   2020年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1029/2019JD032240

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  19. Abundances and Microphysical Properties of Light-Absorbing Iron Oxide and Black Carbon Aerosols Over East Asia and the Arctic 査読有り

    Yoshida Atsushi, Moteki Nobuhiro, Ohata Sho, Mori Tatsuhiro, Koike Makoto, Kondo Yutaka, Matsui Hitoshi, Oshima Naga, Takami Akinori, Kita Kazuyuki

    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES   125 巻 ( 15 )   2020年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Atmospheres  

    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. The particle size distribution for each of the BC and FeOx was similar in all of the data sets except for those dominated by fresh urban pollution or pristine Arctic air. The campaign-averaged mass concentrations of FeOx and BC were ~60–360 ng/m3 and ~240–1,300 ng/m3, respectively, in East Asia, and ~6 ng/m3 and ~20–30 ng/m3, respectively, in the Arctic. The campaign-averaged FeOx/BC mass concentration ratio varied within a narrow range of 0.2–0.6 in both East Asian and Arctic regions. 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.

    DOI: 10.1029/2019JD032301

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    その他リンク: https://onlinelibrary.wiley.com/doi/full-xml/10.1029/2019JD032301

  20. Changes in black carbon and PM<sub>2.5</sub> in Tokyo in 2003-2017. 査読有り

    Mori T, Ohata S, Morino Y, Koike M, Moteki N, Kondo Y

    Proceedings of the Japan Academy. Series B, Physical and biological sciences   96 巻 ( 3 ) 頁: 122-129   2020年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.2183/pjab.96.010

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  21. Concentrations and size distributions of black carbon in the surface snow of Eastern Antarctica in 2011 査読有り

    T. Kinase, K. Adachi, N. Oshima, K. Goto-Azuma, Y. Ogawa-Tsukagawa, M. Shiobara, Y. Kondo, N. Moteki, S. Ohata, T. Mori, M. Hayashi, K. Hara, H. Kawashima, and K. Kita

    Journal of Geophysical Research: Atmospheres   125 巻   2019年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1029/2019JD030737

  22. Black Carbon and Inorganic Aerosols in Arctic Snowpack 査読有り

    Mori Tatsuhiro, Goto-Azuma Kumiko, Kondo Yutaka, Ogawa-Tsukagawa Yoshimi, Miura Kazuhiko, Hirabayashi Motohiro, Oshima Naga, Koike Makoto, Kupiainen Kaarle, Moteki Nobuhiro, Ohata Sho, Sinha P. R., Sugiura Konosuke, Aoki Teruo, Schneebeli Martin, Steffen Konrad, Sato Atsushi, Tsushima Akane, Makarov Vladimir, Omiya Satoshi, Sugimoto Atsuko, Takano Shinya, Nagatsuka Naoko

    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES   124 巻 ( 23 ) 頁: 13325-13356   2019年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1029/2019JD030623

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  23. Accuracy of black carbon measurements by a filter-based absorption photometer with a heated inlet 査読有り 国際共著

    Ohata Sho, Kondo Yutaka, Moteki Nobuhiro, Mori Tatsuhiro, Yoshida Atsushi, Sinha Puna R., Koike Makoto

    AEROSOL SCIENCE AND TECHNOLOGY   53 巻 ( 9 ) 頁: 1079 - 1091   2019年9月

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    担当区分:筆頭著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Aerosol Science and Technology  

    Long-term measurements of black carbon (BC) aerosols by filter-based absorption photometers with a heated inlet (COSMOS) in different regions have been useful in elucidating spatial variations and radiative impacts of BC. Evaluations of mass concentrations of BC (MBC) measured by the COSMOS have been made by our previous studies through comparisons with other measurement techniques. However, how variations in the microphysical properties of BC and the co-existing light scattering aerosols affect the COSMOS measurements should be evaluated in more detail. In this study, we assessed these potential effects under various field environments in the Arctic and in the East Asia. From the slopes of the correlation plots between the MBC values measured by the COSMOS and a single-particle soot photometer, the average accuracy of the COSMOS was estimated as ∼10% in the MBC range 1–3000 ng m−3. On an hourly basis, the estimated sensitivity of the COSMOS MBC values to the changes in the BC size distributions was less than 10%, within the typical variabilities of BC size at individual observation sites. The COSMOS measurements depended little on the mixing states of BC and the concentrations of co-existing light scattering aerosols, except in the maritime air masses of East Asia, where the relative abundance of sea salt to BC was very high. The MBC measured by COSMOS also well agreed with elemental carbon measurements. Our results demonstrate the high reliability of COSMOS measurements under various environments. Copyright © 2019 American Association for Aerosol Research.

    DOI: 10.1080/02786826.2019.1627283

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  24. Glacially sourced dust as a potentially significant source of ice nucleating particles 査読有り 国際共著

    Y. Tobo, K. Adachi, P. J. DeMott, T. C. J. Hill, D. S. Hamilton, N. M. Mahowald, N. Nagatsuka, S. Ohata, J. Uetake, Y. Kondo, and M. Koike

    Nature Geoscience     2019年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: doi: 10.1038/s41561-019-0314-x

  25. Observational constraint of in-cloud supersaturation for simulations of aerosol rainout in atmospheric models 査読有り

    N. Moteki, T. Mori, H. Matsui, S. Ohata

    npj Climate and Atmospheric Science     頁: 2:6   2019年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: doi: 10.1038/s41612-019-0063-y

  26. Abundance and emission flux of the anthropogenic iron oxide aerosols from the East Asian continental outflow 査読有り

    A. Yoshida, S. Ohata, N. Moteki, K. Adachi, T. Mori, M. Koike, and A. Takami

    Journal of Geophysical Research: Atmospheres   123 巻   頁: 11194-11209   2018年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  27. エアロゾルの湿性除去メカニズムに関する観測的研究 招待有り 査読有り

    大畑祥

    天気   65 巻 ( 9 ) 頁: 617-626   2018年9月

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    担当区分:筆頭著者   記述言語:日本語  

  28. Abundance of light-absorbing anthropogenic iron oxide aerosols in the urban atmosphere and their emission sources 査読有り

    S. Ohata, A. Yoshida, N. Moteki, K. Adachi, Y. Takahashi, M. Kurisu, and M. Koike

    Journal of Geophysical Research: Atmospheres   123 巻   頁: 8115-8134   2018年8月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

  29. Anthropogenic combustion iron as a complex climate forcer 査読有り 国際共著

    Matsui Hitoshi, Mahowald Natalie M., Moteki Nobuhiro, Hamilton Douglas S., Ohata Sho, Yoshida Atsushi, Koike Makoto, Scanza Rachel A., Flanner Mark G.

    NATURE COMMUNICATIONS   9 巻 ( 1 ) 頁: 1593   2018年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Nature Communications  

    Atmospheric iron affects the global carbon cycle by modulating ocean biogeochemistry through the deposition of soluble iron to the ocean. Iron emitted by anthropogenic (fossil fuel) combustion is a source of soluble iron that is currently considered less important than other soluble iron sources, such as mineral dust and biomass burning. Here we show that the atmospheric burden of anthropogenic combustion iron is 8 times greater than previous estimates by incorporating recent measurements of anthropogenic magnetite into a global aerosol model. This new estimation increases the total deposition flux of soluble iron to southern oceans (30-90 °S) by 52%, with a larger contribution of anthropogenic combustion iron than dust and biomass burning sources. The direct radiative forcing of anthropogenic magnetite is estimated to be 0.021 W m-2 globally and 0.22 W m-2 over East Asia. Our results demonstrate that anthropogenic combustion iron is a larger and more complex climate forcer than previously thought, and therefore plays a key role in the Earth system.

    DOI: 10.1038/s41467-018-03997-0

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  30. Seasonal progression of the deposition of black carbon by snowfall at Ny-Ålesund, Spitsbergen 査読有り 国際共著

    P. R. Sinha, Y. Kondo, K. Goto-Azuma, Y. Tsukagawa, K. Fukuda, M. Koike, S. Ohata, N. Moteki, T. Mori, N. Oshima, E. J. Forland, M. Irwin, J.-C. Gallet, and C. A. Pedersen

    Journal of Geophysical Research: Atmospheres   123 巻   頁: 997-1016   2018年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  31. Anthropogenic iron oxide aerosols enhance atmospheric heating. 査読有り

    Moteki N, Adachi K, Ohata S, Yoshida A, Harigaya T, Koike M, Kondo Y

    Nature communications   8 巻   頁: 15329   2017年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1038/ncomms15329

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  32. Evaluation of ground-based black carbon measurements by filter-based photometers at two Arctic sites 査読有り

    P. R. Sinha, Y. Kondo, M. Koike, J. A. Ogren, A. Jefferson, T. E. Barrett, R. J. Sheesley, S. Ohata, N. Moteki, H. Coe, D. Liu, M. Irwin, P. Tunved, P.K. Quinn, and Y. Zhao

    Journal of Geophysical Research: Atmospheres   122 巻   頁: 3544-3572   2017年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  33. アラスカ積雪中のブラックカーボンの緯度分布 査読有り

    塚川佳美,東久美子,近藤豊,杉浦幸之助,大畑祥,森樹大,茂木信宏,小池真,平林幹啓,Remi Dallmayr,榎本浩之

    雪氷   78 巻 ( 6 ) 頁: 459-478   2016年11月

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  34. A key process controlling the wet removal of aerosols: new observational evidence 査読有り

    S. Ohata, N. Moteki, T. Mori, M. Koike, and Y. Kondo

    Scientific Reports   6 巻   頁: 34113   2016年10月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: doi: 10.1038/srep34113

  35. Effects of wet deposition on the abundance and size distribution of black carbon in East Asia 査読有り

    Y. Kondo, N. Moteki, N. Oshima, S. Ohata, M. Koike, Y. Shibano, N. Takegawa, and K. Kita

    Journal of Geophysical Research: Atmospheres   121 巻   頁: 4691-4712   2016年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  36. Improved technique for measuring the size distribution of black carbon particles in liquid water 査読有り

    T. Mori, N. Moteki, S. Ohata, M. Koike, K. Goto-Azuma, Y. Miyazaki, and Y. Kondo

    Aerosol Science and Technology   50 巻   頁: 242-254   2016年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  37. Hygroscopicity of materials internally mixed with black carbon measured in Tokyo 査読有り 国際共著

    S. Ohata, J. P. Schwarz, N. Moteki, M. Koike, A. Takami, and Y. Kondo

    Journal of Geophysical Research: Atmospheres   121 巻   頁: 362-381   2016年1月

     詳細を見る

    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

  38. Detection of light-absorbing iron oxide particles using a modified single-particle soot photometer 査読有り 国際共著

    A. Yoshida, N. Moteki, S. Ohata, T. Mori, R. Tada, P. Dagsson-Waldhauserová, and Y. Kondo

    Aerosol Science and Technology   50 巻 ( 3 ) 頁: i-iv   2016年1月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  39. Technique and theoretical approach for quantifying the hygroscopicity of black-carbon-containing aerosol using a single particle soot photometer 査読有り 国際共著

    J. P. Schwarz, A. E. Perring, M. Z. Markovic, R. S. Gao, S. Ohata, J. Langridge, D. Law, R. McLaughlin, and D. W. Fahey

    Journal of Aerosol Science   81 巻   頁: 110-126   2015年1月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  40. Wet deposition of black carbon at a remote site in the East China Sea 査読有り

    T. Mori, Y. Kondo, S. Ohata, N. Moteki, H. Matsui, N. Oshima, and A. Iwasaki

    Journal of Geophysical Research: Atmospheres   119 巻   2014年8月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: doi:10.1002/2014JD022103

  41. Evaluation of a method to measure black carbon particles suspended in rainwater and snow samples 査読有り 国際共著

    S. Ohata, N. Moteki, J. P. Schwarz, D. W. Fahey, and Y. Kondo

      47 巻   頁: 1073-1082   2013年8月

     詳細を見る

    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

  42. Evaluation of a method for measurement of the concentration and size distribution of black carbon particles suspended in rainwater 査読有り

    S. Ohata, N. Moteki, and Y. Kondo.

    Aerosol Science and Technology   45 巻   頁: 1326-1336   2011年6月

     詳細を見る

    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

▼全件表示

MISC 3

  1. 2019年度「エアロゾル・雲・降水の相互作用に関する研究会」報告

    佐藤陽祐,當房豊,山下克也,荒木健太郎,岩崎杉紀,三隅良平,大竹秀明,茂木信宏,齋藤泉,川合秀明,中島孝,中野諭,森樹大,橋本明弘,郭威鎮,勝山祐太,瀬戸里枝,古藤慎之,山田怜史,折笠成宏,田尻拓也,遠藤幸生,近藤誠,大畑祥,松嶋俊樹  

    天気67 巻 ( 11 ) 頁: 665 - 671   2020年11月

  2. 降水雲の過飽和度を観測から制約する:エアロゾル空間分布の予測のために

    茂木信宏,森樹大,松井仁志,大畑祥  

    大気化学研究 ( 41 )   2019年7月

  3. 第17回国際雲・降水会議(ICCP2016)の報告

    三隅良平,岩崎杉紀,道端拓朗,竹見哲也,山下克也,佐藤陽祐,當房豊,大畑祥,橋本明弘,折笠成宏,田尻拓也,村上正隆  

    天気63 巻 ( 11 ) 頁: 862 - 868   2016年11月

講演・口頭発表等 29

  1. Estimates of mass absorption cross sections of black carbon for filter-based absorption photometers in the Arctic 国際共著

    Sho Ohata

    2021年11月16日 

     詳細を見る

    開催年月日: 2021年11月

    記述言語:英語   会議種別:口頭発表(一般)  

  2. SPES法に基づく名古屋都市大気の非水溶性エアロゾルの観測

    大畑祥

    大気化学討論会  2021年11月10日 

     詳細を見る

    開催年月日: 2021年11月

    記述言語:日本語   会議種別:口頭発表(一般)  

  3. SPES法に基づく非水溶性エアロゾルの測定

    大畑祥

    アジア高山域における氷河融解を加速する光吸収性不純物に関する研究集会  2021年11月1日 

     詳細を見る

    開催年月日: 2021年11月

    記述言語:日本語   会議種別:口頭発表(一般)  

  4. Arctic black carbon during PAMARCMiP 2018 and previous aircraft experiments in spring 国際共著

    Sho Ohata

    2021年6月 

     詳細を見る

    開催年月日: 2021年6月

    記述言語:英語   会議種別:口頭発表(一般)  

  5. Estimates of mass absorption cross sections of black carbon for filter-based absorption photometers in the Arctic 国際共著 国際会議

    Sho Ohata

    4th PACES Open Science Meeting  2021年5月 

     詳細を見る

    開催年月日: 2021年5月

    記述言語:英語   会議種別:口頭発表(一般)  

  6. 雪氷中のブラックカーボンの測定方法

    大畑祥

    研究集会:氷河融解を加速する光吸収性不純物に関する研究  2020年10月 

     詳細を見る

    開催年月日: 2020年10月

  7. 大気化学会のロードマップについて

    松井仁志、大畑祥

    2019年度 エアロゾル・雲・降水の相互作用に関する研究集会  2020年2月 

     詳細を見る

    開催年月日: 2020年2月

  8. 日本北部における大気エアロゾル観測拠点の整備

    持田陸宏、大畑祥

    H30年度陸別ユーザーズミーティング  2019年2月 

     詳細を見る

    開催年月日: 2019年2月

  9. 北極におけるエアロゾル・雲の航空機観測

    大畑祥、吉田淳、茂木信宏、足立光司、小池真

    研究集会:航空機観測による気候・地球システム科学研究の推進 

     詳細を見る

    開催年月日: 2018年12月

    記述言語:日本語   会議種別:口頭発表(一般)  

    国名:日本国  

  10. Abundance of light-absorbing anthropogenic iron oxide aerosols in the urban atmosphere and their emission sources 国際会議

    S. Ohata, A. Yoshida, N. Moteki, K. Adachi, Y. Takahashi, M. Kurisu, and M. Koike

    2018 joint 14th iCACGP Quadrennial Symposium/15th IGAC Science Conference 

     詳細を見る

    開催年月日: 2018年9月

    記述言語:英語   会議種別:ポスター発表  

    国名:日本国  

  11. 北極におけるエアロゾル・雲の航空機観測

    大畑祥、吉田淳、茂木信宏、足立光司、小池真

    日本地球惑星科学連合 

     詳細を見る

    開催年月日: 2018年5月

    記述言語:日本語   会議種別:口頭発表(一般)  

    国名:日本国  

  12. Long-term and intensive measurements of black carbon aerosols in the Arctic

    S. Ohata, M. Koike, P. R. Sinha, N. Moteki, K. Goto-Azuma, Y. Ogawa-Tsukagawa, T. Mori, A. Yoshida, Y. Tobo, and Y. Kondo

     詳細を見る

    開催年月日: 2017年12月

    記述言語:英語   会議種別:口頭発表(一般)  

    国名:日本国  

  13. 東京都市大気における黒色酸化鉄の動態と発生源

    大畑祥、茂木信宏、吉田淳、小池真、足立光司、近藤豊

    日本気象学会 

     詳細を見る

    開催年月日: 2017年10月

    記述言語:日本語   会議種別:口頭発表(一般)  

    国名:日本国  

  14. エアロゾル湿性除去メカニズムに関する観測的研究(2017年度山本賞受賞記念講演) 招待有り

    大畑祥

    日本気象学会 

     詳細を見る

    開催年月日: 2017年10月

    記述言語:日本語   会議種別:口頭発表(招待・特別)  

    国名:日本国  

  15. Wet removal of black carbon aerosols controlled by their cloud condensation nuclei activity 国際会議

    S. Ohata, N. Moteki, T. Mori, M. Koike, and Y. Kondo

    International Conference on Clouds and Precipitation 2016 

     詳細を見る

    開催年月日: 2016年7月

    記述言語:英語   会議種別:ポスター発表  

    国名:グレートブリテン・北アイルランド連合王国(英国)  

  16. Hygroscopicity of materials internally mixed with black carbon measured in Tokyo 国際会議

    S. Ohata, J.P. Schwarz, N. Moteki, M. Koike, A. Takami, and Y. Kondo

    AGU Fall Meeting 

     詳細を見る

    開催年月日: 2015年12月

    記述言語:英語   会議種別:ポスター発表  

    国名:アメリカ合衆国  

  17. 大気・降水同時観測によるブラックカーボン湿性除去の研究

    大畑祥、茂木信宏、森樹大、小池真、高見昭憲、近藤豊

    日本気象学会 

     詳細を見る

    開催年月日: 2015年5月

    記述言語:日本語   会議種別:口頭発表(一般)  

    国名:日本国  

  18. 東京におけるブラックカーボン含有粒子の吸湿特性と湿性除去の測定 国際会議

    大畑祥、茂木信宏、森樹大、小池真、高見昭憲、近藤豊

    日本地球惑星科学連合 

     詳細を見る

    開催年月日: 2015年5月

    記述言語:日本語   会議種別:口頭発表(一般)  

    国名:日本国  

  19. Measurement of the hygroscopicity and wet removal of black-carbon-containing particles in the urban atmosphere of Tokyo 国際会議

    S. Ohata, N. Moteki, T. Mori, M. Koike, J. P. Schwarz, and Y. Kondo

    EGU General Assembly 2015 

     詳細を見る

    開催年月日: 2015年4月

    記述言語:英語   会議種別:ポスター発表  

    国名:オーストリア共和国  

  20. ブラックカーボン含有粒子の吸湿性を測定する新手法の開発

    大畑祥、茂木信宏、Joshua P. Schwarz, 近藤豊

    日本地球惑星科学連合 

     詳細を見る

    開催年月日: 2014年5月

    記述言語:日本語   会議種別:ポスター発表  

    国名:日本国  

  21. 雨・雪サンプル中のブラックカーボンの測定法の開発

    大畑祥、茂木信宏、Joshua P. Schwarz, David W. Fahey, 近藤豊

    日本地球惑星科学連合 

     詳細を見る

    開催年月日: 2013年5月

    記述言語:日本語   会議種別:ポスター発表  

    国名:日本国  

  22. Evaluations of the method to measure black carbon particles suspended in rainwater and snow samples 国際会議

    S. Ohata, N. Moteki, J. P. Schwarz, D. W. Fahey, and Y. Kondo

    AGU Fall Meeting 

     詳細を見る

    開催年月日: 2012年12月

    記述言語:英語   会議種別:口頭発表(一般)  

    国名:アメリカ合衆国  

  23. Evaluation of a method for measurement of black carbon particles suspended in rainwater and its application to long-term measurement at a remote site in the East China Sea 国際会議

    S. Ohata, N. Moteki, and Y. Kondo

    AGU Fall Meeting 

     詳細を見る

    開催年月日: 2011年12月

    記述言語:英語   会議種別:ポスター発表  

    国名:アメリカ合衆国  

  24. SP2を用いた雨水中のブラックカーボンの測定法の開発

    大畑祥、茂木信宏、宮川拓真、近藤豊

    日本地球惑星科学連合 

     詳細を見る

    開催年月日: 2011年5月

    記述言語:日本語   会議種別:ポスター発表  

    国名:日本国  

  25. 東京と沖縄における雨水中のブラックカーボン濃度の測定

    大畑祥、茂木信宏、近藤豊

    日本気象学会 

     詳細を見る

    開催年月日: 2011年5月

    記述言語:日本語   会議種別:ポスター発表  

    国名:日本国  

  26. SPES法に基づく非水溶性エアロゾルの測定

    大畑祥

    アジア高山域における氷河融解を加速する光吸収性不純物に関する研究集会  2021年11月 

     詳細を見る

    会議種別:口頭発表(一般)  

    researchmap

  27. Arctic black carbon during PAMARCMiP 2018 and previous aircraft experiments in spring

    S. Ohata, M. Koike, A. Yoshida, N. Moteki, K. Adachi, N. Oshima, H. Matsui, O. Eppers, H. Bozem, M. Zanatta, A. B. Herber

    日本地球惑星科学連合  2021年6月 

     詳細を見る

    会議種別:口頭発表(一般)  

    researchmap

  28. Estimates of mass absorption cross sections of black carbon for filter-based absorption photometers in the Arctic

    S. Ohata, T. Mori, Y. Kondo, S. Sharma, A. Hyvärinen, E. Andrews, P. Tunved, E. Asmi, J. Backman, H. Servomaa, D. Veber, K. Eleftheriadis, S. Vratolis, R. Krejci, P. Zieger, M. Koike, Y. Kanaya, A. Yoshida, N. Moteki, Y. Zhao, Y. Tobo, J. Matsushita, N. Oshima

    第12回極域科学シンポジウム  2021年11月 

     詳細を見る

  29. SPES法に基づく名古屋都市大気の非水溶性エアロゾルの観測

    大畑祥, 茂木信宏, 川中子ひかる, 當房豊, 足立光司, 持田陸宏

    大気化学討論会  2021年11月 

     詳細を見る

    会議種別:口頭発表(一般)  

    researchmap

▼全件表示

共同研究・競争的資金等の研究課題 2

  1. 地球温暖化に関わる北極エアロゾルの動態解明と放射影響評価

    研究課題番号:2-2003  2020年4月 - 2023年3月

    環境研究総合推進費 

      詳細を見る

    担当区分:研究分担者 

  2. 地球温暖化に関わる北極ブラックカーボンとダスト粒子の動態と放射効果

    研究課題番号:2-1703  2017年4月 - 2019年3月

    環境研究総合推進費 

      詳細を見る

    担当区分:研究分担者  資金種別:競争的資金

科研費 8

  1. 大気有機エアロゾルの吸湿性を表現する新指標の探索

    研究課題/研究課題番号:23H00515  2023年4月 - 2027年3月

    科学研究費助成事業  基盤研究(A)

    持田 陸宏, 佐藤 圭, 石塚 紳之介, 木村 勇気, 松井 仁志, 宮崎 雄三, 大畑 祥

      詳細を見る

    担当区分:研究分担者 

    大気中に浮遊するエアロゾルの吸湿性には、地球の生命活動から直接・間接的に生ずる多様な有機物が深く関わっている。この有機エアロゾルの吸湿性を表現する方法の確立は、エアロゾルの気候影響を評価し、大気汚染の対策を講じる上での課題であるが、単純な経験則に頼る既往の試みは正確性・実用性に欠けている。本研究では、有機エアロゾルの吸湿性を原理的に支配するが連続・広域測定が困難な規定因子を量的に把握し、吸湿性を直接的に規定しないが大気モニタリングが可能な代理指標との関係をパラメータ化で結びつけることで、原理と実用性の狭間を埋め、有機エアロゾル吸湿性の表現方法を刷新する。

  2. 光学的オフライン分析に基づく非水溶性エアロゾルの氷晶核への寄与解明

    研究課題/研究課題番号:22K18024  2022年4月 - 2025年3月

    科学研究費助成事業  若手研究

    大畑 祥

      詳細を見る

    担当区分:研究代表者 

    配分額:4550000円 ( 直接経費:3500000円 、 間接経費:1050000円 )

    大気中の鉱物ダストと生物起源粒子は、氷の雲粒(氷晶)を生成する核(氷晶核)として重要な働きをすると考えられているものの、測定の難しさから、大気中の数濃度の変動と氷晶核数への寄与の理解は不十分である。本研究では、近年開発された光学的粒子検出技術をフィルタに捕集した大気エアロゾルの分析に応用することで、これらの粒子の数濃度を測定する手法を確立する。この手法を用いて都市大気と森林大気のエアロゾルを分析し、二つの代表的な大気環境下における鉱物ダストと生物起源粒子の動態と氷晶核数への寄与を定量的に明らかにする。

  3. 夏季西部北太平洋における固体エアロゾルと氷晶核の航空機観測

    研究課題/研究課題番号:22H04488  2022年4月 - 2024年3月

    科学研究費助成事業  新学術領域研究(研究領域提案型)

    大畑 祥

      詳細を見る

    担当区分:研究代表者 

    配分額:20410000円 ( 直接経費:15700000円 、 間接経費:4710000円 )

    大気中の固体エアロゾルは、氷雲粒子(氷晶)を形成する核(氷晶核)として働くため、その発生源や動態の理解が重要課題となっている。本研究では、当該領域研究の計画研究として計画されている2022年夏の航空機観測において、大気エアロゾルをフィルタ上に採取する。採取したエアロゾルを近年開発された新しい光学的手法で分析することにより、夏季西部北太平洋の大気境界層内および自由対流圏中における、代表的な固体エアロゾルである鉱物ダスト等の典型的な数濃度を明らかにする。また、並行した分析により得られる氷晶核数濃度と固体エアロゾル数濃度の対応関係を明らかにする。

  4. 氷河融解を加速する3大光吸収性不純物の定量評価

    研究課題/研究課題番号:20H00196  2020年4月 - 2025年3月

    科学研究費補助金 

      詳細を見る

    担当区分:研究分担者 

  5. 北極におけるエアロゾルの動態と気候影響

    研究課題/研究課題番号:20H00638  2020年4月 - 2024年3月

    科学研究費補助金 

      詳細を見る

    担当区分:研究分担者 

  6. 氷晶核として働く固体エアロゾルの測定器開発

    研究課題/研究課題番号:19K20437  2019年4月 - 2022年3月

    日本学術振興会  科学研究費助成事業  若手研究

    大畑 祥

      詳細を見る

    担当区分:研究代表者 

    配分額:4030000円 ( 直接経費:3100000円 、 間接経費:930000円 )

    雲内部において水雲粒が凍結し氷雲粒を生成する過程は、雲の寿命や光学特性、ひいては気候に大きな影響を及ぼす。水雲粒の凍結が起こるには、水雲粒の内部に氷形成の核となる非水溶性の固体エアロゾルが含まれていることが必要であり、中でも生物由来粒子や鉱物粒子が高い氷形成能力を持つと考えられている。しかし、大気中の生物由来粒子・鉱物粒子を分離して数濃度・粒径を測定する手法は存在せず、それらの動態と氷晶核数への寄与は明らかになっていない。本研究では、この測定を可能にするため、大気中のエアロゾルを水中に捕集し、非水溶性の固体エアロゾルにレーザー光を照射しその散乱光・蛍光を検出する新しい測定器を開発する。
    氷晶核として重要な働きをする大気中の鉱物粒子・生物由来粒子などの非水溶性固体エアロゾルの粒径別数濃度の測定を可能にするため、これらの粒子をポリカーボネートフィルタに採取し、水に分散させてから光学的に測定する分析手法の評価実験を実施した。粒子の光学的な測定には、近年東京大学の研究グループにより確立されたSingle-particle extinction and scattering method(SPES法)を用いた。評価実験について、具体的には、まず粒径と複素屈折率が既知の球形の標準粒子等を用いた実験により、フィルタの粒子捕集効率・フィルタから水への粒子分散効率・光学測定における粒子検出体積をそれぞれ決定した。フィルタから水への粒子分散効率の不確実性が最も大きく、超音波洗浄機やミキサーなど、分散方法によって標準粒子の分散効率が異なることを明らかにした。また、鉱物粒子・生物由来粒子・黒色炭素粒子(BC)のそれぞれの標準試料を用いた実験により、SPES法でこれらの粒子を経験的に分離測定可能であることを確認した。非水溶性固体粒子の中でも、BCはレーザー誘起白熱法(LII法)を用いた大気中・水中の粒径別数濃度の測定法が確立されている。本手法の妥当性をさらに検証することを目的として、LII法に基づくBC測定器と、自家蛍光を検出することにより生物由来粒子の粒径別数濃度を推定する既存の測定器の準備を進めた。また、名古屋の都市大気のエアロゾル試料の継続的な採取を開始した。
    フィルタに採取した鉱物粒子・生物由来粒子・BCなどの非水溶性固体エアロゾルの粒径別数濃度を定量するために必要な評価実験を順調に実施している。
    名古屋の都市大気において、本研究で開発を進めているフィルタ分析手法による測定と既存のBC測定器・生物由来粒子測定器による測定を同時に行うことで、本手法の妥当性を検証する。また、水以外の溶媒に対する固体エアロゾルの分散試験を実施し、より安定した分析や、粒子の化学組成に関する情報を追加で得ることが可能となるか検討を進める。

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  7. 卓越研究員事業

    2018年10月 - 2020年3月

    科学技術人材育成費補助金 

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    担当区分:研究代表者 

    配分額:12000000円 ( 直接経費:12000000円 )

  8. 東アジアにおける黒色炭素粒子の降水による除去過程の解明

    研究課題/研究課題番号:12J06736  2012年4月 - 2015年3月

    科学研究費補助金 

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    担当区分:研究代表者 

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