KEIO RESEARCHERS INFORMATION SYSTEM

Career 【 Display / hide 】

Career 【 Display / hide 】

• 2016.04

  -

  2017.03

  The University of Tokyo, Graduate School of Science, 日本学術振興会 特別研究員(DC2)

• 2017.04

  -

  2021.03

  Tokyo University of Science, Physics, Faculty of Science, Division 1, 嘱託助教

• 2021.04

  -

  2022.03

  The University of Tokyo, Department of Earth and Planetary Science, 特任助教

• 2021.04

  -

  Present

  Tokyo University of Science, 客員研究員

• 2022.04

  -

  Present

  Keio University, Faculty of Science and Technology Department of Applied Chemistry, Assistant professor

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Research Areas 【 Display / hide 】

Research Areas 【 Display / hide 】

• Natural Science / Atmospheric and hydrospheric sciences

• Environmental Science/Agriculture Science / Environmental impact assessment

Research Keywords 【 Display / hide 】

Research Keywords 【 Display / hide 】

• Aerosol, charging states, East Asia, Arctic, Health effect

Books 【 Display / hide 】

Books 【 Display / hide 】

• Aerosol Spatial Distribution Observed by a Mobile Vehicle Lidar with Optics for Near-Range Detection

  Masanori Yabuki, Kazuhiko Miura, Tatsuhiro Mori, Hiroshi Hayami, Hiroaki Kuze, Springer International Publishing, 2023

  　View Summary

  We describe a mobile vehicle lidar that enables near-range observations to achieve continuous monitoring of atmospheric aerosols with high spatiotemporal resolutions. The lidar employed a short-pulse laser of 355-nm wavelength. After passing the beam expander, the outgoing laser energy satisfied the eye-safety requirements, and the laser suspended the emission when detecting an overpass structure in the vehicle’s travel direction. The near-range observation was implemented by slanting a part of the receiving optical axis by placing several wedge prisms in front of the receiver telescope. Normally, lidar observations were made in the vertical direction while driving the vehicle at speeds slower than 50 km/h. Two additional mirrors installed above the car’s sunroof changed the directions of the laser beam and telescope field-of-view to achieve horizontal observation, if necessary. We demonstrated the capability of the proposed lidar system in detecting near-surface aerosol along a travel path of 25 km in the Tokyo Bay area, with an altitude range coverage between 7 and 650 m. Higher boundary layer heights with more significant aerosol loading were found in inland areas than over the coastal streets. Also, we observed aerosols over a rice paddy field of 600 m × 600 m by employing the horizontal observation mode.

  • Access to Document (DOI)

Papers 【 Display / hide 】

Papers 【 Display / hide 】

• Numerical analysis of collision mechanism that causes particle tribocharging in dry powder inhaler

  Ryosuke Mitani, Muhammad Aiman bin Mohd Nor, Takuto Iinuma, Tatsuhiro Mori, Tomoaki Okuda

  Asian Journal of Atmospheric Environment (Springer Science and Business Media LLC)  19 ( 1 )  2025.12

  Research paper (scientific journal), Joint Work, Lead author, Corresponding author, Accepted,  ISSN  19766912

  　View Summary

  Abstract
  
  Chronic obstructive pulmonary disease (COPD) is induced by inhalation of toxic substances such as cigarettes and air pollution. Dry powder inhalers (DPIs) are the primary treatment for these diseases. However, they have some problems, such as residuals in a capsule caused by electrostatic force before reaching the human lungs. This study investigated the particle tribocharging mechanism in a DPI using a tandem differential mobility analyzer (TDMA) and a combined discrete element method and computational fluid dynamics (DEM-CFD) approach. In the TDMA experiment, the charging state of the particles changed from negative to positive charge in the DPI device fabricated by the 3D printer. This is because tribocharging is caused by particle–particle collisions and particle–wall collisions. In the numerical simulation, particle–wall collisions occurred more frequently than particle–particle collisions. Therefore, the particle–wall collisions change the charging state of the particle in the DPI device. These results suggest that collisions between particles and walls of the device cause the particles to become charged, leading to a decrease in their deposition in the deeper regions of the lungs. Moreover, the large turbulence kinetic energy of the airflow in the DPI device caused particle–wall collisions because the particles were widely dispersed in the DPI device. These results suggest that optimum turbulence kinetic energy is necessary to reduce particle aggregation and improve the delivery efficiency of DPIs to the human lungs.
  
  Graphical Abstract

  • Access to Document (DOI)

• Integrated aircraft and research vessel observational studies of aerosols and clouds in summer over the western North Pacific

  Makoto Koike, Yoshimi Kawai, Kouji Adachi, Hidenori Aiki, Yugo Kanaya, Hideaki Kawai, Kazuyuki Kita, Fumiyoshi Kondo, Tsuyoshi Koshiro, Hitoshi Matsui, Takuma Miyakawa, Ayumu Miyamoto, Takafumi Miyasaka, Yuzo Miyazaki, Michihiro Mochida, Tatsuhiro Mori, Nobuhiro Moteki, Toshiyuki Murayama, Hisashi Nakamura, Sho Ohata, Eitarou Oka, Satoru Okajima, Yutaka Tobo, Shion Sekizawa, Atsushi Yoshida

  Progress in Earth and Planetary Science (Springer Science and Business Media LLC)  12 ( 1 )  2025.12

  Research paper (scientific journal), Joint Work, Lead author, Corresponding author, Accepted

  　View Summary

  Abstract
  
  An integrated observational study of aerosols and clouds was carried out in summer 2022 over the western North Pacific (off the eastern coast of Hokkaido, Japan) using both an aircraft and a research vessel for the first time in this area. The aim of this experiment was to characterize the physical and chemical properties of aerosols and to evaluate the contributions of anthropogenic and natural emissions to cloud condensation nuclei (CCN) and ice-nucleating particle (INP) concentrations. The experiment also aims to examine the vertical structure of low-level clouds, which have high radiative effects, over this region. Here, we present an overview of the experiment and some preliminary results. Onboard the research vessel, suspended particulate matter in seawater was sampled, and the size distributions of dominant particle types (e.g., diatom fragments and organic matter) were determined. By analyzing atmospheric aerosols sampled from aircraft, we derived the number size distributions of dust-like particles in the air far from source regions. The aerosol size distributions, as measured from both the vessel and aircraft, suggested that most of the aerosols that could act as CCN were of anthropogenic origin: The upper-bound estimate of the sea spray aerosol (SSA) contribution to the CCN concentration at altitudes below 1200 m was 23%. Numerical model simulations generally reproduced the observed aerosol number concentrations. The simulations supported the inference from the observation that most CCN over the study area were of anthropogenic origin. Using this model, SSA emissions were estimated to account for 9% of the cloud radiative effect. Cloud observations from aircraft revealed that low-level clouds tended to have an adiabatic vertical structure under cold air advection, whereas under warm air advection, they occasionally had a layered structure. Such diverse vertical structures of low-level clouds are not generally seen in the subtropics. The integrated observations carried out in this study provided a basic picture of aerosols and clouds over the study area in summer. Further research is needed to elucidate the roles of aerosols in cloud formation and the radiation budget under various meteorological conditions within the framework of atmosphere–ocean interactions.

  • Access to Document (DOI)

• Individual particle compositions and aerosol mixing states at different altitudes over the ocean in East Asia

  Kouji Adachi, Atsushi Yoshida, Tatsuhiro Mori, Nobuhiro Moteki, Sho Ohata, Kazuyuki Kita, Yoshimi Kawai, Makoto Koike

  Atmospheric Chemistry and Physics (Copernicus GmbH)  25 ( 19 ) 12599 - 12613 2025.10

  Research paper (scientific journal), Joint Work, Lead author, Corresponding author, Accepted,  ISSN  16807316

  　View Summary

  Abstract. Aerosol composition and mixing state influence its ability to form cloud droplets and ice crystals and to scatter and absorb sunlight, all of which affect its impact on climate. In this study, aerosol samples were collected from different altitudes, ranging from the sea surface to ∼ 8000 m, over the ocean in the western North Pacific in the summer of 2022 using an aircraft and a research vessel. The samples were classified into three periods based on the sampled air parcel sources: ocean and desert (period 1), Siberian Forest biomass burning event (period 2), and their mixtures (period 3). Measurements of particle composition using transmission electron microscopy with energy-dispersive X-ray spectrometry revealed that samples from period 1 had high sea salt and mineral dust fractions, whereas samples from period 2 had high fractions of potassium-bearing particles with organics and black carbon. Samples from period 3 showed influences of both sea spray and biomass burning. During periods 1 and 3, the sea salt fractions increased as the samples were collected at lower altitudes. The compositions of biomass burning and sea spray were mixed at individual particles, with higher fractions of Na and K during period 1 and period 2, respectively, than in other periods. Our analysis of individual particles revealed a wide range of compositions and mixing states of particles, which depend on the aerosol source, size, and altitude. These factors need to be considered when evaluating aerosol composition and mixing state, both of which affect aerosol climate effects.

  • Access to Document (DOI)

• Sensitivity of Wintertime Arctic Black Carbon to Removal Processes and Regional Alaskan Sources

  Eleftherios Ioannidis, Kathy S. Law, Jean‐Christophe Raut, Louis Marelle, Tatsuo Onishi, Elisabeth Andrews, Sho Ohata, Tatsuhiro Mori, Sara Morris, Yukata Kondo, Sangeeta Sharma, Konstantinos Eleftheriadis, Zbigniew Klimont, Antonin Soulie, Claire Granier, Patricia K. Quinn, Kerri A. Pratt

  Journal of Geophysical Research: Atmospheres (American Geophysical Union (AGU))  130 ( 7 )  2025.04

  Research paper (scientific journal), Joint Work, Lead author, Corresponding author, Accepted,  ISSN  2169897X

  　View Summary

  Abstract
  
  Air pollutants are primarily transported from midlatitude emission regions in winter and early spring, leading to elevated concentrations of aerosols, including black carbon (BC), in the Arctic, a phenomenon known as Arctic haze. The Weather Research and Forecasting model coupled with chemistry is used to investigate potential causes of uncertainties in modeling Arctic BC for winter 2014. The model captures observed variability in BC at surface sites, reproducing BC concentrations at Zeppelin but showing a low bias at Tiksi, Alert, and Utqiaġvik/Barrow. The influence of removal processes on model BC biases is explored by switching off dry or wet deposition. Wet deposition, during transport in the North Atlantic storm track, and locally over Svalbard, dominates BC removal at Zeppelin, while wet removal in the Pacific storm track influences BC at Alert and Utqiaġvik/Barrow. Dry removal over Asian source regions and Alaska affects BC at Utqiaġvik/Barrow, and is larger than wet removal at Tiksi due to the proximity of local/regional anthropogenic sources. Regional runs over northern Alaska in late January show improved simulated BC compared to observations at Utqiaġvik/Barrow, in part, due to better resolution of removal processes, and local/regional emissions. Sensitivity runs also show that regional Alaskan sources, notably from the North Slope of Alaska oil fields, may be contributing 30%–50%, on average, to observed BC at Utqiaġvik/Barrow in January and February 2014, with the remainder from outside the region. These findings highlight the importance of local Arctic emissions, and the need for improved emission inventories in the Arctic.

  • Access to Document (DOI)

• Aircraft‐Based Observation of Mineral Dust Particles Over the Western North Pacific in Summer Using a Complex Amplitude Sensor

  S. Ohata, N. Moteki, K. Adachi, Y. Tobo, H. Matsui, K. Kita, T. Mori, M. Koike

  Journal of Geophysical Research: Atmospheres 130 ( 5 )  2025.03

  Research paper (scientific journal), Joint Work, Lead author, Corresponding author, Accepted,  ISSN  2169897X

  　View Summary

  Mineral dust accounts for a significant fraction of the atmospheric aerosol burden, impacting climate through its interactions with radiation and clouds. However, limited observations of dust particles in the free troposphere hinder our understanding of its spatial distribution and climatic impacts. In this study, aerosols were collected on filters using aircraft over the western North Pacific at 0.2–8 km altitudes in summer 2022. Individual water-insoluble particles dispersed in water were analyzed using a complex amplitude sensor (CAS), which enabled classifying particle type, sizing, and counting from the particle's complex amplitude data. During the eight observation flights, the number and mass concentrations of dust were 1.2 ± 1.0 cm⁻³ and 0.6 ± 0.4 μg m⁻³ (mean ± 1σ), respectively, in the 0.3–2.5 μm diameter range, which were 2–3 orders of magnitude lower than previously reported values near the major dust sources in East Asia. A comparison with the total aerosol data from an optical particle counter onboard aircraft suggested that dust dominated aerosols larger than 0.8 μm, consistent with electron microscopy analyses. The observed dust size distributions implied more efficient removal of larger dust during transport. Since our samples were collected at −18°C to 21°C, the free tropospheric dust could contribute to ice formation in clouds. Our observation using the CAS revealed microphysical properties of dust over the western North Pacific when no distinct Asian dust events were observed near the ground, aiding in the validation of models that assess the climatic impacts of dust.

  • Access to Document (DOI)

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Papers, etc., Registered in KOARA 【 Display / hide 】

Papers, etc., Registered in KOARA 【 Display / hide 】

• Evaluation of the influence of charging state of atmospheric aerosol on particle deposition on human body and ground surface

  Mori, Tatsuhiro

  科学研究費補助金研究成果報告書 2023

• Observational studies on behaviors of the charged black carbon particles in the air with a new technique for measuring of the charge distribution of black carbon

  Mori, Tatsuhiro

  学事振興資金研究成果実績報告書 (慶應義塾大学)  2022

Reviews, Commentaries, etc. 【 Display / hide 】

Reviews, Commentaries, etc. 【 Display / hide 】

• グリーンランド氷床コアによる最終氷期の急激な気候変動イベントの高時間分解能解析-Dansgaard Oeschgerイベント9~12の連続融解分析-

  東久美子, 福田かおり, 尾形純, 小室悠紀, 小室悠紀, 平林幹啓, 藤田秀二, 藤田秀二, 茂木信宏, 森樹大, 大畑祥, 近藤豊, 小池真, 大藪幾美, 大藪幾美, 北村享太郎, 塚川佳美, 川村賢二, 川村賢二, RASMUSSEN S. O., DAHL-JENSEN D.

  雪氷研究大会講演要旨集(Web) 2024 2024

  Lead author, Corresponding author,  ISSN  1883-0889

• Seasonal charge distributions of submicron atmospheric particles at Noto Peninsula in Japan

  森樹大, 松木篤, 岩田歩, 鴨川仁, 奥田知明

  エアロゾル科学・技術研究討論会(CD-ROM) 41st 2024

  Lead author, Corresponding author

• 横浜と能登における粒子の帯電分布の変動要因

  森樹大, 松木篤, 岩田歩, 鴨川仁, 奥田知明

  大気環境学会年会講演要旨集 65th 2024

  Lead author, Corresponding author

• グリーンランド北東部における産業革命以後のブラックカーボンと硫酸塩エアロゾルの経年変動-アイスコア連続融解分析装置(CFA)によるEGRIP浅層アイスコアの高時間分解能分析-

  東久美子, 東久美子, 福田かおり, 平林幹啓, 尾形純, 小室悠紀, 中澤文男, 中澤文男, 大藪幾美, 北村享太郎, 藤田秀二, 藤田秀二, 茂木信宏, 森樹大, 大畑祥, 近藤豊, 小池真, 栗田直幸, 塚川佳美, 川村賢二, 川村賢二, RASMUSSEN Sune O., SINNL Giulia, POPP Trevor J., DAHL-JENSEN Dorthe

  雪氷研究大会講演要旨集(Web) 2023 2023

  Lead author, Corresponding author,  ISSN  1883-0889

• 都市域における帯電粒子の数濃度分布の季節変化

  森樹大, 石井悠人, 岩田歩, 奥田知明

  大気環境学会年会講演要旨集 64th 2023

  Lead author, Corresponding author

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Presentations 【 Display / hide 】

Presentations 【 Display / hide 】

• 能登における粒子の帯電状態と大気電場との関係

  森樹大, 奥田知明, 松木篤, 岩田歩, 鴨川仁

  日本大気電気学会第103回研究発表会, 

  2025.01

  , 

  Oral presentation (general)

• 横浜と能登における粒子の帯電分布の変動要因

  森樹大, 松木篤, 岩田歩, 鴨川仁, 奥田知明

  第65回大気環境学会年会, 

  2024.09

  , 

  Poster presentation

• 能登における帯電粒子の季節変化と変動要因の解明

  森樹大, 松木篤, 岩田歩, 鴨川仁, 奥田知明

  第41回日本エアロゾル科学・技術研究討論会, 

  2024.08

• 横浜・福岡・能登における微小大気エアロゾル粒子の酸化能

  西田 千春, 中野 康平, 山中 裕子, 森 樹大, 原 圭一郎, 林 政彦, 松木 篤, 奥田 知明

  第41回エアロゾル科学・技術研究討論会, 

  2024.08

• Igor Pro 実践編

  森樹大

  第19回エアロゾル学会若手フォーラム 若手研究者・技術スキルアップセミナー「粒子のデータ解析・可視化に使われるソフトウェア講習会」, 

  2024.01

  , 

  Oral presentation (general)

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Research Projects of Competitive Funds, etc. 【 Display / hide 】

Research Projects of Competitive Funds, etc. 【 Display / hide 】

• 急速な温暖化に伴う北極気候とエアロゾルの相互作用の解明

  2026.04

  -

  2029.03

  環境再生保全機構, 環境研究総合推進費, 環境問題対応型研究（一般課題）, Principal investigator

• 能登における高時間分解能計測した帯電粒子の挙動の解明

  2026

  -

  2027

  金沢大学環日本海域環境研究センター, 環境変化が健康に及ぼす影響に関する研究, Principal investigator

• 東アジアにおけるブラックカーボンの長期変動と気候への影響

  2025.04

  -

  2028.03

  日本学術振興会, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Principal investigator

  　View Summary

  ブラックカーボン（BC）は大きな正の放射強制力を持つ。BC排出量が世界最大である東アジアはBCの発生源として最も重要な地域である。我々は22°Nの台湾から44°Nに位置する北海道までの5つの観測所で長期にわたりBC濃度を高精度で観測してきた。
  本研究ではこれまで得たデータを解析し、BCの空間分布と時間変動を明らかにする。また解析されたデータを地球システムモデル(MRI-ESM2)と比較しモデルの精度を評価する。精度評価されたモデルを用いて、アジアにおけるBCの時空間変動の要因を解明する。またBCの放射効果・気候影響とその時間的推移を明らかにする。

• 発雷時におけるサブミクロン粒子の帯電状態に関する 観測的研究

  2025.04

  -

  2026.03

  金沢大学環日本海域環境研究センター, 環境変化が健康に及ぼす影響に関する研究, Principal investigator

• ブラックカーボンの帯電状態の測定法の開発とその変動要因の観測的解明

  2024.04

  -

  2027.03

  日本学術振興会, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Principal investigator

  　View Summary

  実環境大気中の微小粒子状物質の電荷数を推算する測定技術と、ブラックカーボン（BC）粒子の大きさごとの数・質量濃度を測定する装置を組み合わせることで、BC 粒子の帯電状態を高い時間分解能で観測可能な、新たな手法の確立を目指す。さらに、本測定手法を実大気観測に適用することで、実環境大気中のBCの帯電状態の変動要因を明らかにする。本研究の遂行により、数値モデルで表現されるエアロゾルの帯電メカニズムの表現を適切に精緻化することで、生体内に沈着する BC の粒子数の予測精度が一層向上すると期待される。

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Awards 【 Display / hide 】

Awards 【 Display / hide 】

• 第103回研究発表会 学生発表表彰

  寺坂桃, 森樹大, 奥田知明, 2025.03, 日本大気電気学会, 開閉平行板型帯電分級装置の開発と大気中帯電粒子の化学成分分析

• Paper Award

  速水洋, 伊賀悠太, 三浦和彦, 森樹大, 櫻井達也, 2023.09, 大気環境学会(AJAE部門), Detection of Ship Fuel Sulfur Contents in Exhaust Plumes at the Kanmon Straits, Japan, before and after the Global Sulfur Limit 2020

• 第98回研究発表会 学生発表表彰

  五十嵐博己, 森樹大, 三浦和彦, 岩本洋子, 和田龍一, 加藤俊吾, 大河内博, 2021.01, 日本大気電気学会, 富士山頂における日中と夜間の新粒子生成イベントの長期観測

• 第97回研究発表会 学生発表表彰

  横山慎太郎, 永野勝裕, 三浦和彦, 櫻井達也, 森樹大, 2020.01, 日本大気電気学会, 富士山におけるラドン濃度変動と気塊由来の関係

• 第96回研究発表会 学生発表表彰

  佐藤丈徳, 三浦和彦, 森樹大, 三隅良平, 宇治靖, 當房豊, 岩本洋子, 2019.01, 日本大気電気学会, 2016-2017年の東京スカイツリーで観測された新粒子生成の季節変化

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Courses Taught 【 Display / hide 】

Courses Taught 【 Display / hide 】

• EXERCISE ON CHEMICAL ENGINEERING

  2026

• LABORATORY IN SCIENCE

  2026

• LABORATORIES IN APPLIED CHEMISTRY C

  2026

• LABORATORY IN SCIENCE

  2025

• LABORATORIES IN APPLIED CHEMISTRY C

  2025

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Courses Previously Taught 【 Display / hide 】

Courses Previously Taught 【 Display / hide 】

• 自然科学実験

  慶應義塾大学

  2022.04

  -

  Present

  , 

  Full academic year, Laboratory work/practical work/exercise

• 応用化学実験C

  慶應義塾大学

  2022.04

  -

  Present

  , 

  Full academic year, Laboratory work/practical work/exercise

• 物理学実験

  東京理科大学

  2017.04

  -

  2021.03

  , 

  Full academic year, Laboratory work/practical work/exercise

• 物理数学演習

  東京理科大学

  2017.04

  -

  2021.03

  , 

  Full academic year, Laboratory work/practical work/exercise

Memberships in Academic Societies 【 Display / hide 】

Memberships in Academic Societies 【 Display / hide 】

• Society of Atmospheric Electricity of Japan, 

  2024.04

  -

  Present

• 大気環境学会, 

  2023.04

  -

  Present

• 富士山測候所を活用する会, 

  2017.04

• 日本大気化学会, 

  2014

  -

  Present

• 日本エアロゾル学会, 

  2013

  -

  Present

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Committee Experiences 【 Display / hide 】

Committee Experiences 【 Display / hide 】

• 2024.09

  -

  2025.08

  実行委員会, 第42回日本エアロゾル学会

• 2024.09

  -

  2025.08

  若手会 代表, 日本エアロゾル学会

• 2023.09

  -

  2024.08

  若手会 副代表, 日本エアロゾル学会

• 2023.04

  -

  2024.09

  会場委員会委員長, 第65回大気環境学会年会

• 2022.09

  -

  Present

  Editorial Board of Asian Journal of Atmospheric Environment (AJAE), Asian Journal of Atmospheric Environment

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