藤原 正智 (フジワラ マサトモ)

地球環境科学研究院 地球圏科学部門 大気海洋物理学分野教授

研究者基本情報

■ 学位
  • 博士(理学), 東京大学, 1999年03月
■ URL
researchmap URLホームページURL■ ID 各種
研究者番号
  • 00360941
ORCID IDResearcher ID
  • F-7852-2012
J-Global ID■ 研究キーワード・分野
研究キーワード
  • 大気科学
  • 気象学
研究分野
  • 自然科学一般, 大気水圏科学
■ 担当教育組織

経歴

■ 経歴
経歴
  • 2022年07月 - 現在
    北海道大学, 大学院地球環境科学研究院, 教授, 日本国
  • 2007年04月 - 2022年06月
    北海道大学, 大学院地球環境科学研究院・地球圏科学部門, 准教授
  • 2005年04月 - 2007年03月
    北海道大学, 大学院地球環境科学研究院・地球圏科学部門, 助教授
  • 2003年04月 - 2005年03月
    北海道大学, 大学院地球環境科学研究科・大気海洋圏環境科学専攻, 助教授
  • 2001年04月 - 2003年03月
    京都大学, 宙空電波科学研究センター, 日本学術振興会特別研究員PD
  • 2000年04月 - 2001年03月
    北海道大学, 大学院地球環境科学研究科・大気海洋圏環境科学専攻, 日本学術振興会特別研究員PD
  • 1999年04月 - 2000年03月
    東京大学, 大学院理学系研究科・地球惑星物理学専攻, 日本学術振興会特別研究員PD
  • 1998年04月 - 1999年03月
    東京大学, 大学院理学系研究科・地球惑星物理学専攻, 日本学術振興会特別研究員DC2
学歴
  • 1996年04月 - 1999年03月, 東京大学, 理学系研究科, 地球惑星物理学専攻 博士課程, 日本国
  • 1994年04月 - 1996年03月, 東京大学, 理学系研究科, 地球惑星物理学専攻 修士課程, 日本国
  • 1990年04月 - 1994年03月, 東京大学, 理科I類 ~ 理学部, 地球物理学科, 日本国
委員歴
  • 2025年04月 - 現在
    日本気象学会, 北海道支部幹事, 学協会
  • 2024年03月 - 現在
    GCOS/WCRP AOPC, Working Group on GRUAN, Co-chair, 学協会
  • 2021年07月 - 現在
    環境省・オゾン層保護に関する検討会・科学分科会・委員, 政府
  • 2014年04月 - 現在
    気象庁・長期再解析推進委員会/懇談会, 委員, 政府
  • 2007年12月 - 現在
    日本気象学会, 「天気」北海道地区編集委員, 学協会
  • 2007年03月 - 現在
    日本学術会議, 環境学委員会・地球惑星科学委員会合同 IGBP・WCRP・DVERSITAS合同分科会SPARC小委員会委員, 政府
  • 2006年08月 - 現在
    GCOS/AOPC, Working Group on GRUAN (former WG on Atmospheric Reference Observations, renamed in 2012), Member, 学協会
  • 2016年09月 - 2024年07月
    International Ozone Commission (IO3C), Member, 学協会
  • 2011年06月 - 2024年07月
    WCRP SPARC Reanalysis Intercomparison Project (S-RIP), Co-lead, 学協会
  • 2010年 - 2024年03月
    GRUAN Task Team Radiosonde, Co-chair, 学協会
  • 2018年02月 - 2024年
    WCRP Task Team for Intercomparison of ReAnalyses (TIRA), Co-chair, 学協会
  • 2016年10月 - 2024年
    WCRP Task Team for Intercomparison of ReAnalyses (TIRA), Member, 学協会
  • 2006年07月 - 2022年12月
    日本気象学会, Journal of the Meteorological Society of Japan (JMSJ) 編集委員会委員, 学協会
  • 2017年 - 2020年07月
    Assessment of Operating Procedures for Ozone Sondes (ASOPOS) 2.0, Panel Member, 学協会
  • 2011年07月 - 2019年
    International Commission on the Middle Atmosphere (ICMA), Member, 学協会
  • 2016年07月 - 2017年
    Scientific Steering Committee of the Ozone Data Quality Assessment (O3S-DQA) and the Jülich Ozone Sonde Intercomparison Experiment (JOSIE), Member, 学協会
  • 2004年04月 - 2008年03月
    日本気象学会, 北海道支部幹事, 学協会

研究活動情報

■ 受賞
  • 2025年02月, American Meteorological Society, Scientific and Technological Activities Commission (STAC) Technological Accomplishment Award 2025
    "For exceptional leadership of the SPARC Reanalysis Intercomparison Project and unremitting dedication to developing and evaluating middle atmosphere measurements"
    Masatomo Fujiwara
  • 2024年02月, 日本気象学会, 2023年英文レター誌SOLA論文賞
    Suzuki et al., Development of a new particle imaging radiosonde with particle fall velocity measurements in clouds, Scientific Online Letters on the Atmosphere, 19, 261−268, 2023
    Suzuki, K;Y. Hara;T. Sugidachi;K. Shimizu;M. Fujiwara, 学会誌・学術雑誌による顕彰
  • 2018年, Sustainability Science, 2017 Sustainability Science Best Paper Awards - Outstanding Article (Sugiyama et al., SS, 2017)
    Sugiyama et al., 学会誌・学術雑誌による顕彰
  • 2010年, 日本気象学会, 2010年気象集誌論文賞
    for papers by Sakazaki and Fujiwara (JMSJ, 2010a, 2010b)
    坂崎 貴俊;藤原 正智
  • 2000年, 日本気象学会, 2000年度山本・正野論文賞
    for paper by Fujiwara et al. (JGR, 1998)
    藤原 正智
■ 論文
  • Ozone formation sensitivity based on the secondary formaldehyde-to-nitrogen dioxide ratio (FNR sec ) derived from ground-based remote sensing measurements and a chemical transport model
    Nguyen Doan Thien Chi; Hiroshi Tanimoto; Satoshi Inomata; Kohei Ikeda; Yange Deng; Royston Uning; Tamaki Fujinawa; Astrid Müller; Masatomo Fujiwara; Shungo Kato; Hisahiro Takashima
    Atmospheric Chemistry and Physics, 26, 11, 8275, 8294, Copernicus GmbH, 2026年06月12日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌), Abstract. Sensitivity analysis is essential for developing effective ozone (O3) mitigation strategies. This study aims to extensively investigate the diurnal, seasonal, and vertical chemical sensitivity of O3 using a photochemical indicator, the secondary formaldehyde (HCHO)-to-nitrogen dioxide (NO2) ratio (FNRsec) as measured by Pandora remote-sensing spectrometers located across Japan. Region-specific FNRsec thresholds were determined using the GEOS-Chem chemical transport model. Surface concentrations and vertical column amounts of HCHO and NO2 were obtained from in situ measurements and Pandora spectrometers. The concentrations of HCHO and NO2 varied with season and altitude. Moreover, external pollution transport affected the vertical profiles and likely contributed to elevated concentrations. During exceedance events, the O3 sensitivity analysis showed that NOx-limited conditions were dominant in summer, transitional regimes in spring and fall. Vertically, ROx-limited conditions typically formed near the surface layers, followed by transitional regimes in the mid-levels, and NOx-limited regimes aloft. Therefore, O3 mitigation strategies should target not only the surface level but also elevated altitudes. This study contributes to fostering a comprehensive understanding of O3 sensitivity in the troposphere using FNRsec retrieved from Pandora measurements.
  • Stratosphere‐Troposphere Exchange of Ozone and CO Over the North Pacific: Roles of Different Types of Rossby Wave Breaking With Multiple Chemical‐Reanalysis Perspectives
    Haosen Xi; Masatomo Fujiwara
    Journal of Geophysical Research: Atmospheres, 131, 2026年03月28日, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌)
  • The Asian Summer Monsoon Chemical and Climate Impact Project (ACCLIP): An Overview
    L. L. Pan; E. L. Atlas; P. A. Newman; T. Thornberry; K. W. Jucks; O. B. Toon; W. J. Randel; Q. Liang; D. E. Kinnison; R. Ueyama; J. F. Bresch; S. B. Honomichl; W. P. Smith; R. S. Hornbrook; L. Ziemba; M. Fujiwara; E. C. Apel; M. Barucci; G. Bianchini; M. Brown; T. P. Bui; T. Campos; M. Chin; F. D’Amato; J. Dean‐Day; G. Diskin; A. Franchin; C. Gurganus; L. T. Iraci; J. Kim; J.‐H. Koo; L. R. Lai; K. Lesko; J. R. Podolske; A. Rollins; T. Sakai; K. Shiraishi; V. Treadaway; S. Viciani; E. Waxman
    Journal of Geophysical Research: Atmospheres, 130, 23, American Geophysical Union (AGU), 2025年11月28日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌), Abstract

    The Asian summer monsoon Chemical and Climate Impact Project is centered on a large airborne field campaign investigating the role the Asian Summer Monsoon (ASM) plays in changing the atmospheric composition in the upper troposphere and lower stratosphere. This campaign, conducted in Summer 2022 using two research aircraft, has obtained the most comprehensive data set for chemical composition, including hundreds of trace gas species as well as the physical and chemical properties of aerosols in the ASM convective outflow over East Asia and the Western Pacific. These data show that the ASM deep convection is creating a chemically distinct layer near the tropopause that has large anthropogenic influences. This overview provides a summary of the project, including the scientific objectives, dynamical, and meteorological conditions of the campaign season, key elements of the campaign operations, selected scientific highlights, and ongoing research.
  • Characterization of Pandora Sky-Scan Modes from the Japan Pandora Network and Evaluation of Their Use in Validating Satellite NO 2 and HCHO Retrievals
    Nguyen Doan Thien Chi; Hiroshi Tanimoto; Satoshi Inomata; Tamaki Fujinawa; Astrid Müller; Takafumi Sugita; Shungo Kato; Nobuhiko Kuze; Yugo Kanaya; Masatomo Fujiwara; Jun Hirokawa; Hisahiro Takashima; Tomoo Nagahama; Kazuyo Yamaji; Soichi Hirokawa; Sang-Woo Kim; Prajjwal Rawa; James H. Crawford
    ACS ES&T Air, 2, 2872, 2888, American Chemical Society (ACS), 2025年11月25日, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌)
  • The AquaVIT-4 intercomparison of atmospheric hygrometers
    Simone Brunamonti; Harald Saathoff; Albert Hertzog; Glenn Diskin; Masatomo Fujiwara; Karen Rosenlof; Ottmar Möhler; Béla Tuzson; Lukas Emmenegger; Nadir Amarouche; Georges Durry; Fabien Fréro; Jean-Christophe Samake; Claire Cenac; Julio Lopez; Paul Monnier; Mélanie Ghysels
    Atmospheric Measurement Techniques, 18, 5321, 5348, 2025年10月15日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌)
  • Tropical volcanic impacts on MENA climate via ENSO and NAO dynamics in a high-top model
    Muhammad Mubashar Dogar; Shingo Watanabe; Masatomo Fujiwara; Muhammad Adnan Abid; Turki M. Habeebullah; Basit Khan
    npj Climate and Atmospheric Science, 8, 1, Springer Science and Business Media LLC, 2025年09月29日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌), Abstract

    Volcanic eruptions are among the strongest climate drivers, yet their regional impacts on the Middle East and North Africa (MENA) remain poorly constrained. Post-eruption amplified winter cooling in MENA is often attributed to a volcanically forced positive North Atlantic Oscillation (NAO), but the concurrent occurrence of El Niño–Southern Oscillation (ENSO) complicates attribution. Furthermore, summer climatic responses, including tropical warming and mid-latitude cooling, remain underexplored. Here, we present a pioneering research using a high-top coupled climate model (MIROC6) to assess volcanic-induced ENSO–NAO interactions and their regional climate impacts. We demonstrate that volcanic-induced NAO variability is the primary driver of post-eruption MENA winter cooling, with El Niño acting as a modulator rather than a fundamental trigger. We further reveal distinct summer climate anomalies, including suppressed precipitation over the Intertropical Convergence Zone (ITCZ). These findings underscore the importance of high-top models to resolve stratospheric influences on post-volcanic climate variability.
  • Observational ozone datasets over the global oceans and polar regions (version 2024)
    Yugo Kanaya; Roberto Sommariva; Alfonso Saiz-Lopez; Andrea Mazzeo; Theodore K. Koenig; Kaori Kawana; James E. Johnson; Aurélie Colomb; Pierre Tule; Suzie Molloy; Ian E. Galbally; Rainer Volkamer; Anoop Mahajan; John W. Halfacre; Paul B. Shepson; Julia Schmale; Hélène Ango; Byron Blomquis; Matthew D. Shupe; Detlev Helmig; Junsu Gil; Meehye Lee; Sean C. Coburn; Ivan Ortega; Gao Chen; James Lee; Kenneth C. Aikin; David D. Parrish; John S. Holloway; Thomas B. Ryerson; Ilana B. Pollack; Eric J. Williams; Brian M. Lerner; Andrew J. Weinheimer; Teresa Campos; Frank M. Flocke; J. Ryan Spackman; Ilann Bourgeois; Jeff Peischl; Chelsea R. Thompson; Ralf M. Staebler; Amir A. Aliabadi; Wanmin Gong; Roeland Van Malderen; Anne M. Thompson; Ryan M. Stauffer; Debra E. Kollonige; Juan Carlos; Gómez Martin; Masatomo Fujiwara; Katie Read; Matthew Rowlinson; Keiichi Sato; Junichi Kurokawa; Yoko Iwamoto; Fumikazu Taketani; Hisahiro Takashima; Mónica Navarro-Comas; Marios Panagi; Martin G. Schultz
    Earth System Science Data, 17, 9, 4901, 4932, Copernicus GmbH, 2025年09月26日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌), Abstract. Studying tropospheric ozone over the remote areas of the planet, such as the open oceans and the polar regions, is crucial to understand the role of ozone as a global climate forcer and regulator of atmospheric oxidative capacity. A focus on the pristine oceanic and polar regions complements the available land-based datasets and provides insights into key photochemical and depositional loss processes that control the concentrations and spatiotemporal variability in ozone as well as the physicochemical mechanisms driving these patterns. However, an assessment of the role of ozone over the oceanic and polar regions has been hampered by a lack of comprehensive observational datasets. Here, we present the first comprehensive collection of ozone data over the oceans and the polar regions. The overall dataset consists of 77 ship cruises/buoy-based observations and 48 aircraft-based campaigns. The dataset, consisting of more than 630 000 independent ozone measurement data points covering the period from 1977 to 2022 and an altitude range from the surface to 5000 m (with a focus on the lowest 2000 m), allows systematic analyses of the spatiotemporal distribution and long-term trends over the 11 defined ocean/polar regions. The datasets from ships, buoys, and aircraft are complemented by ozonesonde data from 29 launch sites or field campaigns and by 21 non-polar and 17 polar ground-based station datasets. The datasets contain information on how long the observed air masses were isolated from land, as estimated by backward trajectories from the individual observation points. To extract observations representative of oceanic conditions, we recommend using a subset of the data with an isolation time of 72 h or longer, from the analysis with coincident radon observations. These filtered oceanic and polar data showed typically flat diurnal cycles at high latitudes, whereas daytime decreases in ozone (11 %–16 %) were observed at lower latitudes. The ship/buoy- and aircraft-based datasets presented here will supplement the land-based ones in the TOAR-II (Tropospheric Ozone Assessment Report Phase II) database to provide a fully global assessment of tropospheric ozone. The described dataset is available at https://doi.org/10.17596/0004044 (Kanaya et al., 2025).
  • Justification for high-ascent attainment for balloon radiosonde soundings at GRUAN and other sites
    Masatomo Fujiwara; Bomin Sun; Anthony Reale; Domenico Cimini; Salvatore Larosa; Lori Borg; Christoph von Rohden; Michael Sommer; Ruud Dirksen; Marion Maturilli; Holger Vömel; Rigel Kivi; Bruce Ingleby; Ryan J. Kramer; Belay Demoz; Fabio Madonna; Fabien Carminati; Owen Lewis; Brett Candy; Christopher Thomas; David Edwards; Kensaku Shimizu; Peter Thorne
    Atmospheric Measurement Techniques, 2025年07月07日, [査読有り], [筆頭著者], [国際共著], [国際誌]
    研究論文(学術雑誌)
  • Geostationary Satellites Total Ozone Observations: First Results on Ground‐Based Networks Validation Efforts for TEMPO and GEMS
    Xiaoyi Zhao; Debora Griffin; Vitali Fioletov; Chris McLinden; Xiong Liu; Junsung Park; Irina Petropavlovskikh; Thomas F. Hanisco; James Szykman; Lukas Valin; Eric Baumann; Alexander Cede; Martin Tiefengraber; Manuel Gebetsberger; Itaru Uesato; Xiangdong Zheng; Soi Ahn; Limseok Chang; Won‐Jin Lee; Jae Hwan Kim; Hyunjin Lee; Kanghyun Baek; Alberto Redondas; Masatomo Fujiwara; Ting Wang; Michel Grutter; John C. Houck; David Haffner; Sum Chi Lee
    Geophysical Research Letters, 52, 12, American Geophysical Union (AGU), 2025年06月14日, [査読有り], [国際共著]
    研究論文(学術雑誌), Abstract

    The Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument, launched in April 2023, is North America's first geostationary air pollution monitoring satellite mission. Together with Asia's Geostationary Environment Monitoring Spectrometer (GEMS) launched in 2020 and Europe's upcoming Sentinel‐4, TEMPO contributes to nearly global coverage provided by geostationary satellite constellation. TEMPO and GEMS offer hourly, high‐resolution data of ozone surpassing the once‐daily observations of instruments like the TROPOspheric Monitoring Instrument (TROPOMI) in temporal resolution. This study presents TEMPO's total ozone data, demonstrating TEMPO's ability to observe sudden changes in ozone and UV index. Furthermore, TEMPO and GEMS measurements are validated using ground‐based monitoring networks (Brewer, Dobson, and Pandora). Results show good agreement but also highlight latitude‐dependent discrepancies between the satellite and ground‐based data sets (−2% to 2% for TEMPO, −1% to −3% for GEMS). Findings are further validated using TROPOMI data and reanalysis models.
  • Investigating post-eruption amplified winter cooling in the Middle East and North Africa—unraveling ENSO and NAO dynamics
    Muhammad Mubashar Dogar; Masatomo Fujiwara; Masamichi Ohba; Mansour Almazroui
    Environmental Research Communications, 2025年04月01日, [査読有り], [国際共著], [国際誌]
    研究論文(学術雑誌)
  • Changes in Equatorial Kelvin Wave Activity in the Upper Troposphere and Lower Stratosphere Associated with Interannual Variability of the Upper-Tropospheric Equatorial Zonal Wind
    Junko Suzuki; Noriyuki Nishi; Masatomo Fujiwara; Kunio Yoneyama
    Journal of Climate, 38, 3, 749, 759, American Meteorological Society, 2025年02月01日, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), We investigate the influence of the background wind regime on interannual variability in equatorial Kelvin waves (including both freely propagating ones and convectively coupled ones) in the upper troposphere and lower stratosphere using the ERA5 reanalysis data. We focus on variability in the number of Kelvin wave cases as a function of the background westerly wind that controls wave propagation, given by the zonal wind index (ZWI) in the equatorial eastern Pacific that is a measure of the strength of the upper branch of the Walker circulation in the Western Hemisphere. The ZWI correlates well with sea surface temperature in the Niño-3.4 region, though one-third of the peaks of negative ZWI (weak westerly) cases occur during seasons other than December–February which is the typical El Niño season. In the positive ZWI (stronger westerly) cases, both the convective activity over the western Pacific and the extratropical Rossby wave activity over the central and eastern Pacific are enhanced. Kelvin waves over the Western Hemisphere appear frequently at 200 hPa but barely reach 100 hPa due to the strong westerly wind below this level that prohibits upward wave propagation. In the negative ZWI period, the number of Kelvin wave cases at 200 hPa decreases due to weaker convection; Kelvin waves reach 100 hPa and propagate even further upward into the stratosphere. The increasing (decreasing) tendency of Kelvin waves already starts 6 months before the weakest (strongest) westerly wind month in the Western Hemisphere (i.e., the ENSO peak seasons).

    Significance Statement

    Equatorial Kelvin waves play a critical role in the upward transport of momentum driving the equatorial stratospheric circulation. Our results reveal that background winds in the upper troposphere and the lower stratosphere act as a filter for equatorial Kelvin waves, regulating the number of their packets propagating upward. An investigation of the role of Kelvin wave dissipation in the westerly duct region, i.e., in the upper troposphere over the equatorial eastern Pacific, is needed.
  • Development of a Peltier-based chilled-mirror hygrometer, SKYDEW, for tropospheric and lower-stratospheric water vapor measurements
    Takuji Sugidachi; Masatomo Fujiwara; Kensaku Shimizu; Shin-Ya Ogino; Junko Suzuki; Ruud J. Dirksen
    Atmospheric Measurement Techniques, 18, 2, 509, 531, Copernicus GmbH, 2025年01月28日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌), We have developed a Peltier-based non-cryogenic chilled-mirror hygrometer named SKYDEW to measure water vapor from the surface to the stratosphere. Several chamber experiments were conducted to investigate the characteristics and performance of the instrument under various conditions. The stability of the feedback controller that maintains the condensate on the mirror depends on the controller setting, the condensate condition, and the frost point in ambient air. The results of condensate observation by a microscope and proportional-integral-derivative (PID) tuning in a chamber were used to determine the PID parameters of the controller such that slight oscillations of the scattered light signal from the mirror and mirror temperature are retained. This allows for the detection of steep gradients in the humidity profile, which are otherwise not detected because of the slower response. The oscillation of the raw mirror temperature is smoothed with a golden point method that selects the equilibrium point of the frost layer. We further describe the details of the data processing and the uncertainty estimation for SKYDEW measurements in terms of the Global Climate Observing System (GCOS) Reference Upper-Air Network (GRUAN) requirements. The calibration uncertainty of the mirror temperature measurement is < 0.1 K for the entire temperature range from −95 to 40 °C. The total measurement uncertainty of SKYDEW measurements can exceed 0.5 K in regions where large oscillations of the mirror temperature remain. Intercomparisons with relative humidity (RH) sensors on radiosondes, the cryogenic frost point hygrometer (CFH), and the Aura Microwave Limb Sounder (MLS) were performed at various latitudes in the Northern Hemisphere to evaluate the performance of SKYDEW. These results show that SKYDEW can reliably measure atmospheric water vapor up to 25 km altitude. Data from several SKYDEW and CFH measurements predominantly agree within their respective uncertainties, although a systematic difference of ∼ 0.5 K between SKYDEW and CFH was found in the stratosphere, the reason for which is unknown. SKYDEW shows good agreement with Aura MLS for profiles that are not affected by contamination.
  • Thermal Characteristics of the Extreme Cases of Tropopause Over the Tropics
    Pooja Purushotham; Sanjay Kumar Mehta; Saleem Ali; Masatomo Fujiwara; Susann Tegtmeier
    International Journal of Climatology, 44, 16, 5934, 5949, Wiley, 2024年11月08日, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), The anomalous variability of extreme cases of the tropical tropopause provides insight into the stratosphere‐troposphere exchange process crucial for understanding climate change. The present study analyses the extreme variability of the tropopause and its thermal structure over the tropics using GPS radio occultation data over the period 2006–2019. The extremely cold and warm tropopauses and extremely high and low tropopauses are identified based on the cold point tropopause temperature and height, respectively, when their values exceed two standard deviations with respect to their climatological means. The analyses revealed frequent occurrence of extreme cases of tropopause over the Atlantic Ocean compared to the Western Pacific Ocean. Individually, extremely warm and low cases occur more frequently over the subtropics, while extremely cold and high cases occur frequently over the deep tropics. These extreme cases pose different thermal structures bounded within the extremely low and high tropopauses throughout the tropics. The height difference between the extremely high and low tropopause cases is wider over the Atlantic Ocean and adjoining areas compared to the western Pacific Ocean. The temperature difference between the extremely warm and cold tropopause cases is higher in the Atlantic, Central Pacific, and Indonesian regions compared to the American, Indian Ocean, and western Pacific Ocean regions. The relationship between the El Niño Southern Oscillation (ENSO) phases and extreme tropopause cases is also investigated which reveals a higher occurrence of extremely high tropopause cases during the El Niño phase while low tropopause cases during the La Niña phase. Our analysis also revealed the thermal patterns of the extreme cases characterising colder and sharper tropopause over the convective regions compared to subsidence regions.
  • Characteristics of convection and advection associated with the Asian Summer Monsoon Anticyclone
    P. P. Musaid; Sanjay Kumar Mehta; Susann Tegtmeier; Masatomo Fujiwara; Siddarth Shankar Das; Someshwar Das
    Climate Dynamics, 62, 9, 8929, 8945, Springer Science and Business Media LLC, 2024年08月08日, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), The Asian Summer Monsoon Anticyclone (ASMA) is a gateway for atmospheric pollutants transported to the upper troposphere and lower stratosphere (UTLS). Thus, it is necessary to understand the relative roles of vertical transport due to convection and horizontal transport due to advection in the formation and sustenance of the ASMA. Outgoing longwave radiation reveals that the ASMA region shows characteristic features associated with strong convective activity in its eastern (70°–120° E) part while subsidence dominates in the western (20°–70° E) part. Over the convective region, the convergence of latent heat flux extends from the Indian mainland (65°–110° E) to the west Pacific Warm Pool (WP) (110°–160° E). On average the ASMA region is characterized by a main convective outflow level at ~ 9 km. This level varies considerably with longitude being higher (~ 10.5 km) over the convective region and lower (~ 7 km) over the subsidence region. Furthermore, the mean convective outflow level is higher over the WP (11.5 km) region when compared to the Indian mainland (10 km) region. From the thermodynamic energy equation, we have calculated the convective and advective terms and found anomalously cold advection over the subsidence region and warm advection over the convective region. The warm advection over the convective region is split into two parts with the stronger one located over the Indian region and the weaker one over the WP region. Similarly, stronger convection occurs over the Indian mainland (convective term ~ 4 K/day) compared to the WP (~ 1 K/day). The cold advection over the subsidence region is mainly centered near 30° E longitude. The convection over the Indian region and the cold advection over the subsidence region as well as warm advection and convection over the WP region are associated. We find that the advective terms change in magnitude and shift together with the convective terms in response to signals of the El Nino Southern Oscillation and the Indian Ocean Dipole.
  • Identification of the Asian summer monsoon anticyclone based on tropical easterly and subtropical westerly jets during active and break phases
    Padinhare Peediyekkal Musaid; Sanjay Kumar Mehta; Susann Tegtmeier; Masatomo Fujiwara; Pooja Purushotham; Sachin Philip Kakkanattu; Karaikkattu Benzigar Betsy; Chengannikkattu Jayakrishnan Seetha
    International Journal of Climatology, 44, 12, 4260, 4285, Wiley, 2024年08月, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), The Asian summer monsoon anticyclone (ASMA) plays a vital role in the transport and redistribution of the tracers in the upper troposphere and lower stratosphere during transient monsoon conditions. The ASMA can be identified using various diagnostics such as winds and divergence, potential vorticity, the Montgomery stream function or geopotential height. Its representation based on the commonly‐used existing method that takes a climatological range of the geopotential height (GPH) at a given pressure level is not robust and fails in several circumstances. In this study, we propose a new GPH method to define the ASMA for the active and break phases of the monsoon based on the GPH values at the tropical easterly jet (TEJ) and subtropical westerly jet (STJ) locations. The proposed method compares the GPH values at the locations corresponding to the wind speed maxima of TEJ and STJ at 100 hPa with the maximum GPH at 100 hPa and selects the one with the minimum difference to define the ASMA extent. The same procedures were applied to obtain the ASMA extent at 150 hPa. The ASMA extents are obtained using the method proposed here and the existing fixed GPH method for the 30 active and 27 break phases from 2005 to 2023. The fixed GPH method provides a larger ASMA extent for 24 active and 21 break phases, which appears to be an unrealistic estimation compared to the proposed method. Our proposed method identifies the ASMA extent that is larger and centred around the Iranian side during the active phases while it is smaller and centred around the Tibetan side during the break phases. Furthermore, the minimum concentration of ozone (O3), and maximum concentrations of carbon monoxide (CO) and water vapour (H2O) are also found to be centred near the Iranian side during the active phases and on the Tibetan side during the break phases. The tracer concentrations are generally higher for CO, H2O and O3 during the active phase than in the break phase. Tracer concentrations within the ASMA extent using the fixed GPH method are higher for O3 while lesser for CO and H2O when compared to the proposed method.
  • Climatology of the terms and variables of transformed Eulerian-mean (TEM) equations from multiple reanalyses: MERRA-2, JRA-55, ERA-Interim, and CFSR
    Masatomo Fujiwara; Patrick Martineau; Jonathon S. Wrigh; Marta Abalos; Petr Šácha; Yoshio Kawatani; Sean M. Davis; Thomas Birner; Beatriz M. Monge-Sanz
    Atmospheric Chemistry and Physics, 24, 7873, 7898, 2024年07月10日, [査読有り], [筆頭著者, 責任著者], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌), A 30-year (1980–2010) climatology of the major variables and terms of the transformed Eulerian-mean (TEM) momentum and thermodynamic equations is constructed by using four global atmospheric reanalyses: the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2); the Japanese 55-year Reanalysis (JRA-55); the European Centre for Medium-Range Weather Forecasts (ECMWF) interim reanalysis (ERA-Interim); and the Climate Forecast System Reanalysis (CFSR). Both the reanalysis ensemble mean (REM) and the differences in each reanalysis from the REM are investigated in the latitude–pressure domain for December–January–February and for June–July–August. For the REM investigation, two residual vertical velocities (the original one and one evaluated from residual meridional velocity) and two mass streamfunctions (from meridional and vertical velocities) are compared. Longwave (LW) radiative heating and shortwave (SW) radiative heating are also shown and discussed. For the TEM equations, the residual terms are also calculated and investigated for their potential usefulness, as the residual term for the momentum equation should include the effects of parameterized processes such as gravity waves, while that for the thermodynamic equation should indicate the analysis increment. Inter-reanalysis differences are investigated for the mass streamfunction, LW and SW heating, the two major terms of the TEM momentum equation (the Coriolis term and the Eliassen–Palm flux divergence term), and the two major terms of the TEM thermodynamic equation (the vertical temperature advection term and the total diabatic heating term). The spread among reanalysis TEM momentum balance terms is around 10 % in Northern Hemisphere winter and up to 50 % in Southern Hemisphere winter. The largest uncertainties in the thermodynamic equation (about 50 %) are found in the vertical advection, for which the structure is inconsistent with the differences in heating. The results shown in this paper provide basic information on the degree of agreement among recent reanalyses in the stratosphere and upper troposphere in the TEM framework.
  • ENSO and NAO Linkage to Strong Volcanism and Associated Post‐Volcanic High‐Latitude Winter Warming
    Muhammad Mubashar Dogar; Masatomo Fujiwara; Ming Zhao; Masamichi Ohba; Yu Kosaka
    Geophysical Research Letters, 51, 1, American Geophysical Union (AGU), 2024年01月08日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌), Abstract

    High‐latitude winter warming was observed following strong tropical volcanism, which has long been believed to be due to the volcanic‐induced positive North Atlantic Oscillation (NAO) phase. However, recent works argue that this warming is caused by El Niño–Southern Oscillation (ENSO) variability instead of volcanoes. Moreover, some studies further argue that El Niño and volcanoes work together to produce this post‐volcanic NAO winter warming. To better understand these arguments on post‐volcanic high‐latitude winter warming, we conducted ENSO‐preconditioned volcanic experiments. Our simulations strongly suggest that the post‐eruption Eurasian winter warming is caused by a post‐eruption positive NAO phase and not by coexisting ENSO‐preconditioned variability. Additionally, we find that the El Niño‐preconditioned volcanic eruption enhances the El Niño phase; however, the neutral and La Niña‐preconditioned eruptions do not lead to an ENSO–like response. These findings are helpful to better understand volcanic‐induced circulation impacts and have important implications for the interpretation of model results and post‐volcanic prediction.
  • Development of a new particle imaging radiosonde with particle fall velocity measurements in clouds
    Kenji Suzuki; Yurika Hara; Takuji Sugidachi; Kensaku Shimizu; Masatomo Fujiwara
    SOLA (Scientific Online Letters on the Atmosphere), 19, 251, 254, 2023年09月, [査読有り]
    英語, 研究論文(学術雑誌)
  • LODEWAVE (LOng-Duration balloon Experiment of gravity WAVE over Antarctica)
    Tomikawa, Y; K. Sato; Y. Saito; I. Murata; N. Hirasawa; M. Kohma; K. Nakashino; D. Akita; T. Matsuo; M. Fujiwara; T. Kaho; L. Yoshida
    Journal of Evolving Space Activities, 1, 2023年03月, [査読有り]
    英語, 研究論文(国際会議プロシーディングス)
  • A Review of El Niño Southern Oscillation Linkage to Strong Volcanic Eruptions and Post-Volcanic Winter Warming
    Muhammad Mubashar Dogar; Leon Hermanson; Adam A. Scaife; Daniele Visioni; Ming Zhao; Ibrahim Hotei; Hans-F. Graf; Muhammad Ahmad Dogar; Mansour Almazroui; Masatomo Fujiwara
    Earth Systems and Environment, 7, 1, 15, 42, Springer Science and Business Media LLC, 2022年11月07日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌)
  • Comparison of GRUAN data products for Meisei iMS-100 and Vaisala RS92 radiosondes at Tateno, Japan
    Shunsuke Hoshino; Takuji Sugidachi; Kensaku Shimizu; Eriko Kobayashi; Masatomo Fujiwara; Masami Iwabuchi
    Atmospheric Measurement Techniques, 15, 20, 5917, 5948, Copernicus GmbH, 2022年10月19日, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), Abstract. A total of 99 dual soundings with Meisei iMS-100 radiosonde and Vaisala RS92 radiosondes were carried out at the Aerological Observatory of the Japan Meteorological Agency, known as Tateno (36.06∘ N, 140.13∘ E, 25.2 m; the World Meteorological Organization, WMO, station number 47646), from September 2017 to January 2020. Global Climate Observing System (GCOS) Reference Upper-Air Network (GRUAN) data products (GDPs) from both sets of radiosonde data for 59 flights were subsequently created using a documented processing programme along with the provision of optimal estimates for measurement uncertainty. Differences in radiosonde performance were then quantified using these GDPs. For daytime observations, the iMS-100 temperature is around 0.5 K cooler than RS92-GDP in the stratosphere, with significant differences in the upper troposphere and lower stratosphere in consideration of combined uncertainties. For nighttime observations, the difference is around −0.1 K, and data are mostly in agreement. For relative humidity (RH), iMS-100 is around 1 % RH–2 % RH higher in the troposphere and 1 % RH smaller in the stratosphere than RS92, but both GDPs are in agreement for most of the profile. The mean pressure difference is ≤0.1 hPa, the wind speed difference is from −0.04 to +0.14 m s−1, the wind direction difference is ≤6.4∘, and the root mean square vector difference (RMSVD) for wind is ≤1.04 m s−1.
  • Balloon-borne aerosol–cloud interaction studies (BACIS): field campaigns to understand and quantify aerosol effects on clouds
    Varaha Ravi Kiran; Madineni Venkat Ratnam; Masatomo Fujiwara; Herman Russchenberg; Frank G. Wienhold; Bomidi Lakshmi Madhavan; Mekalathur Roja Raman; Renju Nandan; Sivan Thankamani Akhil Raj; Alladi Hemanth Kumar; Saginela Ravindra Babu
    Atmospheric Measurement Techniques, 15, 16, 4709, 4734, Copernicus GmbH, 2022年08月19日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌), Abstract. A better understanding of aerosol–cloud interaction processes is importantto quantify the role of clouds and aerosols on the climate system. Therehave been significant efforts to explain the ways aerosols modulate cloudproperties. However, from the observational point of view, it is indeedchallenging to observe and/or verify some of these processes because nosingle instrument or platform has been proven to be sufficient. Discrimination betweenaerosol and cloud is vital for the quantification of aerosol–cloudinteraction. With this motivation, a set of observational field campaignsnamed balloon-borne aerosol–cloud interaction studies (BACIS) is proposedand conducted using balloon-borne in situ measurements in addition to theground-based (lidar; mesosphere, stratosphere and troposphere (MST) radar; lower atmospheric wind profiler; microwave radiometer; ceilometer) and space-borne(CALIPSO) remote sensing instruments from Gadanki (13.45∘ N, 79.2∘ E), India. So far, 15 campaigns have been conducted as a part of BACIS campaignsfrom 2017 to 2020. This paper presents the concept of the observationalapproach, lists the major objectives of the campaigns, describes theinstruments deployed, and discusses results from selected campaigns.Balloon-borne measurements of aerosol and cloud backscatter ratio and cloudparticle count are qualitatively assessed using the range-corrected datafrom simultaneous observations of ground-based and space-borne lidars.Aerosol and cloud vertical profiles obtained in multi-instrumental observationsare found to reasonably agree. Apart from this, balloon-borne profiling isfound to provide information on clouds missed by ground-based and/orspace-borne lidar. A combination of the Compact Optical Backscatter AerosoL Detector (COBALD) and Cloud Particle Sensor (CPS) sonde is employed for the first time in this study to discriminate cloud and aerosol in an in situ profile. A threshold value of the COBALD colour index (CI) for ice clouds is found to be between 18 and 20, and CI values for coarse-mode aerosol particles range between 11 and 15. Using the data from balloon measurements, the relationship between cloud and aerosol is quantified for the liquid clouds. A statistically significant slope (aerosol–cloud interaction index) of 0.77 found between aerosol backscatter and cloud particle count reveals the role of aerosol in the cloud activation process. In a nutshell, the results presented here demonstrate the observational approach to quantifying aerosol–cloud interactions.
  • Cause of a Lower‐Tropospheric High‐Ozone Layer in Spring Over Hanoi
    S.‐Y. Ogino; K. Miyazaki; M. Fujiwara; M. I. Nodzu; M. Shiotani; F. Hasebe; J. Matsumoto; J. Witte; A. M. Thompson; H. A. Nguyen‐Thi; T. V. Nguyen
    Journal of Geophysical Research: Atmospheres, 127, 10, American Geophysical Union (AGU), 2022年05月13日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌)
  • SPARC Report No. 10, WCRP Report 6/2021
    Fujiwara, Masatomo; Manney, Gloria; Gray, Lesley; Wright, Jonathon
    SPARC Office, 2022年
    英語
  • Lower-stratospheric aerosol measurements in eastward-shedding vortices over Japan from the Asian summer monsoon anticyclone during the summer of 2018
    Masatomo Fujiwara; Tetsu Sakai; Tomohiro Nagai; Koichi Shiraishi; Yoichi Inai; Sergey Khaykin; Haosen Xi; Takashi Shibata; Masato Shiotani; Laura L. Pan
    Atmospheric Chemistry and Physics, 21, 4, 3073, 3090, Copernicus GmbH, 2021年03月01日, [査読有り], [筆頭著者], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌), Abstract. Eastward air-mass transport from the Asian summer monsoon (ASM) anticyclone in the upper troposphere and lower stratosphere (UTLS) often involves eastward-shedding vortices, which can cover most of the Japanese archipelago. We investigated the aerosol characteristics of these vortices by analysing data from two lidar systems in Japan, at Tsukuba (36.1∘ N, 140.1∘ E) and Fukuoka (33.55∘ N, 130.36∘ E), during the summer of 2018. We observed several events with enhanced particle signals at Tsukuba at 15.5–18 km of altitude (at or above the local tropopause) during August–September 2018, with a backscattering ratio of ∼ 1.10 and particle depolarization of ∼ 5 % (i.e. not spherical, but more spherical than ice crystals). These particle characteristics may be consistent with those of solid aerosol particles, such as ammonium nitrate. Each event had a timescale of a few days. During the same study period, we also observed similar enhanced particle signals in the lower stratosphere at Fukuoka. The upper troposphere is often covered by cirrus clouds at both lidar sites. Backward trajectory calculations for these sites for days with enhanced particle signals in the lower stratosphere and days without indicate that the former air masses originated within the ASM anticyclone and the latter more from edge regions. Reanalysis carbon monoxide and satellite water vapour data indicate that eastward-shedding vortices were involved in the observed aerosol enhancements. Satellite aerosol data confirm that the period and latitudinal region were free from the direct influence of documented volcanic eruptions and high-latitude forest fires. Our results indicate that the Asian tropopause aerosol layer (ATAL) over the ASM region extends east towards Japan in association with the eastward-shedding vortices and that lidar systems in Japan can detect at least the lower-stratospheric portion of the ATAL during periods when the lower stratosphere is undisturbed by volcanic eruptions and forest fires. The upper-tropospheric portion of the ATAL is either depleted by tropospheric processes (convection and wet scavenging) during eastward transport or is obscured by much stronger cirrus cloud signals.
  • Aerological Measurements
    Holger Vömel; Masatomo Fujiwara
    2021年
  • Balloon-borne radiation measurements demonstrate radiative forcing by water vapor and clouds
    Rolf Philipona; Andreas Kräuchi; Rigel Kivi; Thomas Peter; Martin Wild; Ruud Dirksen; Masatomo Fujiwara; Miho Sekiguchi; Dale F. Hurst; Ralf Becker
    Meteorologische Zeitschrift, 29, 6, 501, 509, Schweizerbart, 2020年11月25日, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), Solar shortwave and terrestrial thermal longwave irradiance are measured at radiation sites at the Earth's surface and on satellite platforms high up in space, since many years. Radiation profiles through the Earth's atmosphere, however, have only sporadically been measured from enhanced upper-air radiosondes. Here we show profiles of solar and terrestrial radiation measured with balloon-borne radiometers through cloud-free and cloudy atmospheres, which reveal radiative effects of temperature, water vapor, ozone and clouds on downward and upward radiation. Shortwave radiation profiles show solar absorption in the free atmosphere and strong reflection in clouds and albedo effects on the ground and the atmosphere above. Longwave upward radiation profiles visualize terrestrial radiation emitted from the Earth's surface, which is partly absorbed and reemitted in the boundary layer and in the atmosphere by water vapor and other greenhouse gases. Longwave downward radiation profiles show the absorbed terrestrial radiation in the atmosphere and reveal the warming effect of increasing greenhouse gases, and by this visualize and demonstrate radiative forcing and a changing greenhouse effect by water vapor in the Earth's atmosphere. Longwave net radiation profiles show terrestrial emission into space to be reduced by water vapor and clouds. Measured radiation profiles are compared to numerically calculated radiation profiles.
  • Assessment of Observational Evidence for Direct Convective Hydration of the Lower Stratosphere
    E. J. Jensen; Laura L. Pan; Shawn Honomichl; Glenn S. Diskin; Martina Krämer; Nicole Spelten; Gebhard Günther; Dale F. Hurst; Masatomo Fujiwara; Holger Vömel; Henry B. Selkirk; Junko Suzuki; Michael J. Schwartz; Jessica B. Smith
    Journal of Geophysical Research: Atmospheres, 125, 15, American Geophysical Union (AGU), 2020年08月16日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌), In situ and remote sensing observations of water vapor are analyzed to assess the evidence for direct convective hydration of the lower stratosphere. We have examined several hundred balloon-borne and airborne in situ measurements of lower stratospheric humidity in the tropics and northern midlatitudes. We find that the tropical lower stratospheric H2O enhancements above the background occur quite infrequently, and the height of the enhancements is within about 1 km of the cold-point tropopause. Following Schwartz et al. (2013, https://doi.org/10.1002/grl.50421), we examine the anomalously high (above 8 ppmv) water vapor mixing ratios retrieved by the Aura Microwave Limb Sounder (MLS) at 100- and 82-hPa pressure levels, and we determine their vertical location relative to the local tropopause based on both Global Forecast System (GFS) operational analysis and the ERA5 reanalysis temperature data. We find that essentially all of the >8-ppmv MLS water vapor measurements over the extratropical North American monsoon region are above the relatively low lapse-rate tropopause in the region, and most are above the local cold-point tropopause. Over the Asian monsoon region, most (80/90%) of the high H2O values occur below the relatively high-altitude local lapse-rate/cold-point tropopause. Anomalously high MLS water vapor retrievals at 100 and 82 hPa almost never occur in the deep tropics. We show that this result is consistent with the in situ observations given the broad vertical averaging kernel of the MLS measurement. The available evidence suggests that direct hydration of the lower stratosphere is important over North America during the monsoon season but likely has limited impact in the tropics.
  • Representation of the equatorial stratopause semiannual oscillation in global atmospheric reanalyses
    Yoshio Kawatani; Toshihiko Hirooka; Kevin Hamilton; Anne K. Smith; Masatomo Fujiwara
    Atmospheric Chemistry and Physics, 20, 14, 9115, 9133, Copernicus GmbH, 2020年07月31日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌), Abstract. This paper reports on a project to compare the representation of the semiannual oscillation (SAO)
    in the equatorial stratosphere and lower mesosphere within six major global atmospheric reanalysis
    datasets and with recent satellite Sounding of the Atmosphere Using Broadband Emission Radiometry (SABER) and Microwave Limb Sounder (MLS) observations. All reanalyses have a good
    representation of the quasi-biennial oscillation (QBO) in the equatorial lower and middle
    stratosphere and each displays a clear SAO centered near the stratopause. However, the differences
    among reanalyses are much more substantial in the SAO region than in the QBO-dominated region. The
    degree of disagreement among the reanalyses is characterized by the standard deviation (SD) of the
    monthly mean zonal wind and temperature; this depends on latitude, longitude, height, and
    time. The zonal wind SD displays a prominent equatorial maximum that increases with height, while
    the temperature SD reaches a minimum near the Equator and is largest in the polar regions. Along the Equator,
    the zonal wind SD is smallest around the longitude of Singapore, where consistently high-quality
    near-equatorial radiosonde observations are available. Interestingly, the near-Singapore minimum
    in SD is evident to at least ∼3 hPa, i.e., considerably higher than the usual
    ∼10 hPa ceiling for in situ radiosonde observations. Our measurement of the
    agreement among the reanalyses shows systematic improvement over the period considered
    (1980–2016), up to near the stratopause. Characteristics of the SAO at 1 hPa, such as its
    detailed time variation and the displacement off the Equator of the zonal wind SAO amplitude
    maximum, differ significantly among the reanalyses. Disagreement among the reanalyses becomes
    still greater above 1 hPa. One of the reanalyses in our study also has a version produced
    without assimilating satellite observations, and a comparison of the SAO in these two versions
    demonstrates the very great importance of satellite-derived temperatures in the realistic analysis
    of the tropical upper stratospheric circulation.
  • Use of automatic radiosonde launchers to measure temperature and humidity profiles from the GRUAN perspective
    Fabio Madonna; Rigel Kivi; Jean-Charles Dupont; Bruce Ingleby; Masatomo Fujiwara; Gonzague Romanens; Miguel Hernandez; Xavier Calbet; Marco Rosoldi; Aldo Giunta; Tomi Karppinen; Masami Iwabuchi; Shunsuke Hoshino; Christoph von Rohden; Peter William Thorne
    Atmospheric Measurement Techniques, 13, 7, 3621, 3649, Copernicus GmbH, 2020年07月08日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌), Abstract. In the last two decades, technological progress has not only seen
    improvements to the quality of atmospheric upper-air observations but also
    provided the opportunity to design and implement automated systems able to
    replace measurement procedures typically performed manually. Radiosoundings,
    which remain one of the primary data sources for weather and climate
    applications, are still largely performed around the world manually,
    although increasingly fully automated upper-air observations are used, from
    urban areas to the remotest locations, which minimize operating costs and
    challenges in performing radiosounding launches. This analysis presents a
    first step to demonstrating the reliability of the automatic radiosonde
    launchers (ARLs) provided by Vaisala, Meteomodem and Meisei. The metadata
    and datasets collected by a few existing ARLs operated by the Global
    Climate Observing System (GCOS) Reference Upper-Air Network (GRUAN) certified or
    candidate sites (Sodankylä, Payerne, Trappes, Potenza) have been
    investigated and a comparative analysis of the technical performance (i.e.
    manual versus ARL) is reported. The performance of ARLs is evaluated as being
    similar or superior to those achieved with the traditional manual launches
    in terms of percentage of successful launches, balloon burst and ascent
    speed. For both temperature and relative humidity, the ground-check
    comparisons showed a negative bias of a few tenths of a degree and % RH,
    respectively. Two datasets of parallel soundings between manual and
    ARL-based measurements, using identical sonde models, provided by
    Sodankylä and Faa'a stations, showed mean differences between the ARL and
    manual launches smaller than ±0.2 K up to 10 hPa for the temperature
    profiles. For relative humidity, differences were smaller than 1 % RH for
    the Sodankylä dataset up to 300 hPa, while they were smaller than
    0.7 % RH for Faa'a station. Finally, the observation-minus-background
    (O–B) mean and root mean square (rms) statistics for German RS92 and RS41 stations, which
    operate a mix of manual and ARL launch protocols, calculated using the European Centre for Medium-Range Weather Forecasts (ECMWF)
    forecast model, are very similar, although RS41 shows larger rms(O–B)
    differences for ARL stations, in particular for temperature and wind. A
    discussion of the potential next steps proposed by GRUAN community and other
    parties is provided, with the aim to lay the basis for the elaboration of a
    strategy to fully demonstrate the value of ARLs and guarantee that the
    provided products are traceable and suitable for the creation of GRUAN data
    products.
  • Surface temperature response to the major volcanic eruptions in multiple reanalysis data sets
    Masatomo Fujiwara; Patrick Martineau; Jonathon S. Wright
    Atmospheric Chemistry and Physics, 20, 1, 345, 374, Copernicus GmbH, 2020年01月10日, [査読有り], [筆頭著者], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌), Abstract. The global response of air temperature at 2 m above
    the surface to the eruptions of Mount Agung in March 1963, El Chichón in
    April 1982, and Mount Pinatubo in June 1991 is investigated using 11 global
    atmospheric reanalysis data sets (JRA-55, JRA-25, MERRA-2, MERRA,
    ERA-Interim, ERA-40, CFSR, NCEP-NCAR R-1, 20CR version 2c, ERA-20C, and
    CERA-20C). Multiple linear regression (MLR) is applied to the monthly mean
    time series of temperature for two periods – 1980–2010 (for 10 reanalyses) and 1958–2001 (for 6 reanalyses) – by considering explanatory factors of
    seasonal harmonics, linear trends, quasi-biennial oscillation (QBO), solar
    cycle, tropical sea surface temperature (SST) variations in the Pacific,
    Indian, and Atlantic Oceans, and Arctic SST variations. Empirical orthogonal
    function (EOF) analysis is applied to these climatic indices to obtain a set
    of orthogonal indices to be used for the MLR. The residuals of the MLR are
    used to define the volcanic signals for the three eruptions separately.
    First, area-averaged time series of the residuals are investigated and
    compared with the results from previous studies. Then, the geographical
    distribution of the response during the peak cooling period after each
    eruption is investigated. In general, different reanalyses show similar
    geographical patterns of the response, but with the largest differences in
    the polar regions. The Pinatubo response shows the largest average cooling in
    the 60∘ N–60∘ S region among the three eruptions, with
    a peak cooling of 0.10–0.15 K. The El Chichón response shows slightly
    larger cooling in the NH than in the Southern Hemisphere (SH), while the
    Agung response shows larger cooling in the SH. These hemispheric differences
    are consistent with the distribution of stratospheric aerosol optical depth
    after these eruptions; however, the peak cooling after these two eruptions
    is comparable in magnitude to unexplained cooling events in other periods
    without volcanic influence. Other methods in which the MLR model is used
    with different sets of indices are also tested, and it is found that careful
    treatment of tropical SST variability is necessary to evaluate the surface
    response to volcanic eruptions in observations and reanalyses.
  • Large-and-Sparse-particle Clouds (LSC): Clouds which are subvisible for space-borne lidar and observable for space-borne cloud radar
    Suginori Iwasaki; Takafumi Seguchi; Hajime Okamoto; Kaori Sato; Shuichiro Katagiri; Masatomo Fujiwara; Takashi Shibata; Kazuhisa Tsuboki; Takashi Ono; Takuji Sugidachi
    Polar Science, 21, 117, 123, 2019年09月, [査読有り], [国内誌]
    英語, 研究論文(学術雑誌)
  • Comparison of equatorial wave activity in the tropical tropopause layer and stratosphere represented in reanalyses
    Young-Ha Kim; George N. Kiladis; John R. Albers; Juliana Dias; Masatomo Fujiwara; James A. Anstey; In-Sun Song; Corwin J. Wright; Yoshio Kawatani; François Lott; Changhyun Yoo
    Atmospheric Chemistry and Physics, 19, 15, 10027, 10050, Copernicus GmbH, 2019年08月09日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌), Abstract. Equatorial Kelvin and mixed Rossby–gravity (MRG) waves in the tropical tropopause layer and stratosphere represented in recent reanalyses for the period of 1981–2010 are compared in terms of spectral characteristics, spatial structures, long-term variations, and their forcing of the quasi-biennial oscillation (QBO).
    For both wave types, the spectral distributions are broadly similar among most of the reanalyses, while the peak amplitudes exhibit considerable spread.
    The longitudinal distributions and spatial patterns of wave perturbations show reasonable agreement between the reanalyses.
    A few exceptions to the similarity of the spectral shapes and spatial structures among them are also noted.
    While the interannual variations of wave activity appear to be coherent for both the Kelvin and MRG waves, there is substantial variability in long-term trends among the reanalyses.
    Most of the reanalyses which assimilate satellite data exhibit large increasing trends in wave variance (∼15 %–50 % increase in 30 years at 100–10 hPa), whereas one reanalysis (Japanese 55-year Reanalysis assimilating conventional observations only; JRA-55C) produced without satellite data does not.
    Several discontinuities are found around 1998 in the time series of the Kelvin and MRG wave variances, which manifest in different ways depending on the reanalysis, and are indicative of impacts of the transition of satellite measurements during that year.
    The equatorial wave forcing of the QBO, estimated by the Eliassen–Palm (EP) flux divergence, occurs in similar phase-speed ranges in the lower stratosphere among the reanalyses.
    However, the EP flux and its divergence are found to be dependent on the zonal-mean winds represented in reanalyses, exhibiting different magnitudes, altitudes, and phase-speed ranges of the Kelvin wave forcing between the reanalyses, especially at 20–10 hPa.
    In addition, at around 20 hPa, a wave signal which appears only in easterly mean winds with westward phase speeds is found and discussed.
  • Comparison of the GRUAN data products for Meisei RS-11G and Vaisala RS92-SGP radiosondes at Tateno (36.06° N, 140.13° E), Japan
    Eriko Kobayashi; Shunsuke Hoshino; Masami Iwabuchi; Takuji Sugidachi; Kensaku Shimizu; Masatomo Fujiwara
    Atmospheric Measurement Techniques, 12, 6, 3039, 3065, Copernicus GmbH, 2019年06月04日, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), Abstract. A total of 87 dual flights of Meisei RS-11G radiosondes
    and Vaisala RS92-SGP radiosondes were carried out at the Aerological
    Observatory of the Japan Meteorological Agency (36.06∘ N,
    140.13∘ E, 25.2 m) from April 2015 to June 2017. Global
    Climate Observing System (GCOS) Reference Upper-Air Network (GRUAN) data
    products from both sets of radiosonde data for 52 flights were subsequently
    created using a documented processing program along with the provision of
    optimal estimates for measurement uncertainty. Differences in the
    performance of the radiosondes were then quantified using the GRUAN data
    products. The temperature measurements of RS-11G were, on average,
    0.4 K
    lower than those of RS92-SGP in the stratosphere for daytime observations.
    The relative humidity measurements of RS-11G were, on average, 2 % RH (relative humidity) lower
    than those of RS92-SGP under 90 % RH–100 % RH conditions, while RS-11G gave on
    average 5 % RH higher values than RS92-SGP under ≤50 % RH
    conditions. The results from a dual flight of RS-11G and a cryogenic
    frost point hygrometer (CFH) also showed that RS-11G gave 1 % RH–10 % RH higher
    values than the CFH in the troposphere. Differences between the RS-11G and
    RS92-SGP temperature and relative humidity measurements, based on combined
    uncertainties, were also investigated to clarify major influences behind the
    differences. It was found that temperature differences in the stratosphere
    during daytime observation were within the range of uncertainty (k=2),
    and that sensor orientation is the major source of uncertainty in the
    RS92-SGP temperature measurement, while sensor albedo is the major source of
    uncertainty for RS-11G. The relative humidity difference in the troposphere
    was larger than the uncertainty (k=2) after the radiosondes had passed
    through the cloud layer, and the temperature–humidity dependence correction
    was the major source of uncertainty in RS-11G relative humidity measurement.
    Uncertainties for all soundings were also statistically investigated. Most
    nighttime temperature measurements for pressures of >10 hPa
    were in agreement, while relative humidity in the middle troposphere
    exhibited significant differences. Around half of all daytime temperature
    measurements at pressures of ≤150 hPa and relative humidity
    measurements around the 500 hPa level were not in agreement.
  • Influence of ENSO and MJO on the zonal structure of tropical tropopause inversion layer using high-resolution temperature profiles retrieved from COSMIC GPS Radio Occultation
    Noersomadi; Toshitaka Tsuda; Masatomo Fujiwara
    Atmospheric Chemistry and Physics, 19, 10, 6985, 7000, Copernicus GmbH, 2019年05月24日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌), Abstract. Using COSMIC GPS Radio Occultation (RO) observations from
    January 2007 to December 2016, we retrieved temperature profiles with the
    height resolution of about 0.1 km in the upper troposphere and lower
    stratosphere (UTLS). We investigated the distribution of static stability
    (N2) and the zonal structure of the tropopause inversion layer (TIL) in
    the tropics, where a large change in the temperature gradient occurs associated
    with sharp variations in N2. We show the variations in the mean N2
    profiles in coordinates relative to the cold-point tropopause (CPT). A very
    thin (<1 km) layer is found with average maximum N2 in the
    range of 11.0–12.0×10-4 s−2. The mean and standard
    deviation of TIL sharpness, defined as the difference between the maximum
    N2 (max⁡N2) and minimum N2 (min⁡N2)
    within ±1 km of the CPT, is (10.5±3.7)×10-4 s−2. The max⁡N2 is typically located within 0.5 km above CPT. We focused on the variation in TIL sharpness in two longitude regions,
    90–150∘ E (Maritime Continent; MC) and 170–230∘ E
    (Pacific Ocean; PO), with different land–sea distribution. Seasonal
    variations in TIL sharpness and thickness were related to the deep convective
    activity represented by low outgoing longwave radiation (OLR) during the
    Australian and Asian monsoons. The deviation from the mean sharpness
    (sharpness anomaly) was out of phase with the OLR anomaly in both the MC and
    PO. The correlation between the sharpness anomaly over the MC and PO and the sea
    surface temperature (SST) Niño 3.4 index was −0.66 and +0.88,
    respectively. During La Niña (SST Niño 3.4 <-0.5 K) in the MC and
    El Niño (SST Niño 3.4 >+0.5 K) in the PO, warmer SSTs in the MC
    and PO produce more active deep convection that tends to force the air upward
    to the tropopause layer and increase the temperature gradient there. The
    intraseasonal variation in sharpness anomaly during slow and fast episodes
    of the Madden–Julian Oscillation (MJO) demonstrates that eastward
    propagation of the positive sharpness anomaly is associated with organized deep
    convection. Deep convection during MJO will tend to decrease N2 below
    CPT and increase N2 above CPT, thus enlarging the TIL sharpness. Convective
    activity in the tropics is a major control on variations in tropopause
    sharpness at intraseasonal to interannual timescales.
  • Radiosondes Show That After Decades of Cooling, the Lower Stratosphere Is Now Warming
    Rolf Philipona; Carl Mears; Masatomo Fujiwara; Pierre Jeannet; Peter Thorne; Greg Bodeker; Leopold Haimberger; Maxime Hervo; Christoph Popp; Gonzague Romanens; Wolfgang Steinbrecht; Rene Stübi; Roeland Van Malderen
    Journal of Geophysical Research: Atmospheres, 123, 22, American Geophysical Union (AGU), 2018年11月27日, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), Since the mid-twentieth century, radiosonde and satellite measurements show that the troposphere has warmed and the stratosphere has cooled. These changes are primarily due to increasing concentrations of well-mixed greenhouse gases and the depletion of stratospheric ozone. In response to continued greenhouse gas increases and stratospheric ozone depletion, climate models project continued tropospheric warming and stratospheric cooling over the coming decades. Global average satellite observations of lower stratospheric temperatures exhibit no significant trends since the turn of the century. In contrast, an analysis of vertically resolved radiosonde measurements from 60 stations shows an increase of lower stratospheric temperature since the turn of the century at altitudes between 15 and 30 km and over most continents. Trend estimates are somewhat sensitive to homogeneity assessment choices, but all investigated radiosonde data sets suggest a change from late twentieth century cooling to early 21st century warming in the lower stratosphere, which is consistent with a reversal from ozone depletion to recovery from the effects of ozone-depleting substances. In comparison, satellite observations at the radiosonde locations show only minor early 21st century warming, possibly due to the compensating effects of continued cooling above the radiosonde altitude range.
  • Zonal-mean data set of global atmospheric reanalyses on pressure levels
    Patrick Martineau; Jonathon S. Wright; Nuanliang Zhu; Masatomo Fujiwara
    Earth System Science Data, 10, 4, 1925, 1941, Copernicus GmbH, 2018年10月18日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌), Abstract. This data set, which is prepared for the Stratosphere–troposphere Processes And their Role in Climate (SPARC) Reanalysis
    Intercomparison Project (S-RIP), provides several zonal-mean diagnostics
    computed from reanalysis data on pressure levels. Diagnostics are currently
    provided for a variety of reanalyses, including ERA-40, ERA-Interim, ERA-20C,
    NCEP–NCAR, NCEP–DOE, CFSR, 20CR v2 and v2c, JRA-25, JRA-55, JRA-55C,
    JRA-55AMIP, MERRA, and MERRA-2. The data set will be expanded to include
    additional reanalyses as they become available. Basic dynamical variables
    (such as temperature, geopotential height, and three-dimensional winds) are
    provided in addition to a complete set of terms from the Eulerian-mean and
    transformed-Eulerian-mean momentum equations. Total diabatic heating and its
    long-wave and shortwave components are included as availability permits,
    along with heating rates diagnosed from the basic dynamical variables using
    the zonal-mean thermodynamic equation. Two versions of the data set are
    provided, one that uses horizontal and vertical grids provided by the various
    reanalysis centers and another that uses a common grid (CG) to facilitate
    comparison among data sets. For the common grid, all diagnostics are
    interpolated horizontally onto a regular 2.5∘×2.5∘ grid
    for a subset of pressure levels that are common among all included
    reanalyses. The dynamical
    (Martineau, 2017, https://doi.org/10.5285/b241a7f536a244749662360bd7839312)
    and diabatic
    (Wright, 2017, https://doi.org/10.5285/70146c789eda4296a3c3ab6706931d56)
    variables are archived and maintained by the Centre for Environmental Data
    Analysis (CEDA).
  • Balloon-borne tropospheric CO2 observations over the equatorial eastern and western Pacific
    Yoichi Inai; Shuji Aoki; Hideyuki Honda; Hiroshi Furutani; Yutaka Matsumi; Mai Ouchi; Satoshi Sugawara; Fumio Hasebe; Mitsuo Uematsu; Masatomo Fujiwara
    Atmospheric Environment, 184, 24, 36, 2018年07月, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌)
  • Coordinated Upper-Troposphere-to-Stratosphere Balloon Experiment in Biak
    F. Hasebe; S. Aoki; S. Morimoto; Y. Inai; T. Nakazawa; S. Sugawara; C. Ikeda; H. Honda; H. Yamazaki; Halimurrahman; N. Komala; F. A. Putri; A. Budiyono; M. Soedjarwo; S. Ishidoya; S. Toyoda; T. Shibata; M. Hayashi; N. Eguchi; N. Nishi; M. Fujiwara; S.-Y. Ogino; M. Shiotani; T. Sugidachi
    Bulletin of the American Meteorological Society, 99, 6, 1213, 1230, 2018年06月, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌)
  • Representation of solar tides in the stratosphere and lower mesosphere in state-of-the-art reanalyses and in satellite observations
    Takatoshi Sakazaki; Masatomo Fujiwara; Masato Shiotani
    Atmospheric Chemistry and Physics, 18, 2, 1437, 1456, 2018年02月01日, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌)
  • First Reprocessing of Southern Hemisphere Additional Ozonesondes (SHADOZ) Ozone Profiles (1998–2016): 2. Comparisons With Satellites and Ground‐Based Instruments
    Anne M. Thompson; Jacquelyn C. Witte; Chance Sterling; Allen Jordan; Bryan J. Johnson; Samuel J. Oltmans; Masatomo Fujiwara; Holger Vömel; Marc Allaart; Ankie Piters; Gert J. R. Coetzee; Françoise Posny; Ernesto Corrales; Jorge Andres Diaz; Christian Félix; Ninong Komala; Nga Lai; H. T. Ahn Nguyen; Matakite Maata; Francis Mani; Zamuna Zainal; Shin‐ya Ogino; Francisco Paredes; Tercio Luiz Bezerra Penha; Francisco Raimundo Silva; Sukarni Sallons‐Mitro; Henry B. Selkirk; F. J. Schmidlin; Rene Stübi; Kennedy Thiongo
    Journal of Geophysical Research: Atmospheres, 122, 23, 2017年12月16日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌)
  • Climatology and interannual variability of dynamic variables in multiple reanalyses evaluated by the SPARC Reanalysis Intercomparison Project (S-RIP)
    Craig S. Long; Masatomo Fujiwara; Sean Davis; Daniel M. Mitchell; Corwin J. Wright
    Atmospheric Chemistry and Physics, 17, 23, 14593, 14629, 2017年12月07日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌)
  • Assessment of upper tropospheric and stratospheric water vapor and ozone in reanalyses as part of S-RIP
    Sean M. Davis; Michaela I. Hegglin; Masatomo Fujiwara; Rossana Dragani; Yayoi Harada; Chiaki Kobayashi; Craig Long; Gloria L. Manney; Eric R. Nash; Gerald L. Potter; Susann Tegtmeier; Tao Wang; Krzysztof Wargan; Jonathon S. Wright
    Atmospheric Chemistry and Physics, 17, 20, 12743, 12778, 2017年10月26日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌)
  • Validation of 10-year SAO OMI Ozone Profile (PROFOZ) product using ozonesonde observations
    Guanyu Huang; Xiong Liu; Kelly Chance; Kai Yang; Pawan K. Bhartia; Zhaonan Cai; Marc Allaart; Gérard Ancellet; Bertrand Calpini; Gerrie J; R. Coetzee; Emilio Cuevas-Agulló; Manuel Cupeiro; Hugo De Backer; Manvendra K. Dubey; Henry E. Fuelberg; Masatomo Fujiwara; Sophie Godin-Beekmann; Tristan J. Hall; Bryan Johnson; Everette Joseph; Rigel Kivi; Bogumil Kois; Ninong Komala; Gert König-Langlo; Giovanni Laneve; Thierry Leblanc; Marion Marchand; Kenneth R. Minschwaner; Gary Morris; Michael J. Newchurch; Shin-Ya Ogino; Nozomu Ohkawara; Ankie J. M. Piters; Françoise Posny; Richard Querel; Rinus Scheele; Frank J. Schmidlin; Russell C. Schnell; Otto Schrems; Henry Selkirk; Masato Shiotani; Pavla Skrivánková; René Stübi; Ghassan Taha; David W. Tarasick; Anne M. Thompson; Valérie Thouret; Matthew B. Tully; Roeland Van Malderen; Holger Vömel; Peter von der Gathen; Jacquelyn C. Witte; Margarita Yela
    Atmospheric Measurement Techniques, 10, 7, 2455, 2475, 2017年07月13日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌)
  • The Asia-Pacific’s role in the emerging solar geoengineering debate
    Masahiro Sugiyama; Shinichiro Asayama; Atsushi Ishii; Takanobu Kosugi; John C. Moore; Jolene Lin; Penehuro F. Lefale; Wil Burns; Masatomo Fujiwara; Arunabha Ghosh; Joshua Horton; Atsushi Kurosawa; Andy Parker; Michael Thompson; Pak-Hang Wong; Lili Xia
    Climatic Change, 143, 1-2, 1, 12, 2017年07月, [査読有り], [国際共著]
    英語, 研究論文(学術雑誌)
  • First reprocessing of Southern Hemisphere ADditional OZonesondes (SHADOZ) profile records (1998-2015): 1. Methodology and evaluation
    Jacquelyn C. Witte; Anne M. Thompson; Herman G. J. Smit; Masatomo Fujiwara; Françoise Posny; Gert J. R. Coetzee; Edward T. Northam; Bryan J. Johnson; Chance W. Sterling; Maznorizan Mohamad; Shin-Ya Ogino; Allen Jordan; Francisco R; da Silva
    Journal of Geophysical Research: Atmospheres, 122, 12, 6611, 6636, 2017年06月27日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌)
  • Introduction to the SPARC Reanalysis Intercomparison Project (S-RIP) and overview of the reanalysis systems
    Masatomo Fujiwara; Jonathon S. Wright; Gloria L. Manney; Lesley J. Gray; James Anstey; Thomas Birner; Sean Davis; Edwin P. Gerber; V. Lynn Harvey; Michaela I. Hegglin; Cameron R. Homeyer; John A. Knox; Kirstin Krüger; Alyn Lambert; Craig S. Long; Patrick Martineau; Andrea Molod; Beatriz M. Monge-Sanz; Michelle L. Santee; Susann Tegtmeier; Simon Chabrillat; David G. H. Tan; David R. Jackson; Saroja Polavarapu; Gilbert P. Compo; Rossana Dragani; Wesley Ebisuzaki; Yayoi Harada; Chiaki Kobayashi; Will McCarty; Kazutoshi Onogi; Steven Pawson; Adrian Simmons; Krzysztof Wargan; Jeffrey S. Whitaker; Cheng-Zhi Zou
    Atmospheric Chemistry and Physics, 17, 2, 1417, 1452, 2017年01月31日, [査読有り], [筆頭著者], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌)
  • Transdisciplinary co-design of scientific research agendas: 40 research questions for socially relevant climate engineering research
    Masahiro Sugiyama; Shinichiro Asayama; Takanobu Kosugi; Atsushi Ishii; Seita Emori; Jiro Adachi; Keigo Akimoto; Masatomo Fujiwara; Tomoko Hasegawa; Yasushi Hibi; Kimiko Hirata; Toru Ishii; Takeshi Kaburagi; Yuki Kita; Shigeki Kobayashi; Atsushi Kurosawa; Manabu Kuwata; Kooiti Masuda; Makoto Mitsui; Taku Miyata; Hiroshi Mizutani; Sumie Nakayama; Kazuyo Oyamada; Takaaki Sashida; Miho Sekiguchi; Kiyoshi Takahashi; Yukari Takamura; Junichi Taki; Taketoshi Taniguchi; Hiroyuki Tezuka; Takahiro Ueno; Shingo Watanabe; Rie Watanabe; Naoyuki Yamagishi; Go Yoshizawa
    Sustainability Science, 12, 1, 31, 44, 2017年01月, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌)
  • Development of a cloud particle sensor for radiosonde sounding
    Masatomo Fujiwara; Takuji Sugidachi; Toru Arai; Kensaku Shimizu; Mayumi Hayashi; Yasuhisa Noma; Hideaki Kawagita; Kazuo Sagara; Taro Nakagawa; Satoshi Okumura; Yoichi Inai; Takashi Shibata; Suginori Iwasaki; Atsushi Shimizu
    Atmospheric Measurement Techniques, 9, 12, 5911, 5931, 2016年12月09日, [査読有り], [筆頭著者], [国際誌]
    英語, 研究論文(学術雑誌)
  • Influence of topography on temperature variations in the tropical tropopause layer
    Hiroyasu Kubokawa; Masaki Satoh; Junko Suzuki; Masatomo Fujiwara
    Journal of Geophysical Research: Atmospheres, 121, 19, 11556, 11574, 2016年10月16日, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌)
  • The Stratospheric Water and Ozone Satellite Homogenized (SWOOSH) database:a long-term database for climate studies
    Sean M. Davis; Karen H. Rosenlof; Birgit Hassler; Dale F. Hurst; William G. Read; Holger Vömel; Henry Selkirk; Masatomo Fujiwara; Robert Damadeo
    Earth System Science Data, 8, 2, 461, 490, 2016年09月28日, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌)
  • Representation of the tropical stratospheric zonal wind in global atmospheric reanalyses
    Yoshio Kawatani; Kevin Hamilton; Kazuyuki Miyazaki; Masatomo Fujiwara; James A. Anstey
    Atmospheric Chemistry and Physics, 16, 11, 6681, 6699, 2016年, [査読有り], [国際共著], [国際誌]
    英語, 研究論文(学術雑誌)
  • Signatures of naturally induced variability in the atmosphere using multiple reanalysis datasets
    D. M. Mitchell; L. J. Gray; M. Fujiwara; T. Hibino; J. A. Anstey; W. Ebisuzaki; Y. Harada; C. Long; S. Misios; P. A. Stott; D. Tan
    QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, 141, 691, 2011, 2031, 2015年07月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Effect of recent minor volcanic eruptions on temperatures in the upper troposphere and lower stratosphere
    Sanjay Kumar Mehta; Masatomo Fujiwara; Toshitaka Tsuda; Jean-Paul Vernier
    JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, 129, 99, 110, 2015年07月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Global temperature response to the major volcanic eruptions in multiple reanalysis data sets
    M. Fujiwara; T. Hibino; S. K. Mehta; L. Gray; D. Mitchell; J. Anstey
    ATMOSPHERIC CHEMISTRY AND PHYSICS, 15, 23, 13507, 13518, 2015年, [査読有り]
    英語, 研究論文(学術雑誌)
  • Altitude misestimation caused by the Vaisala RS80 pressure bias and its impact on meteorological profiles
    Y. Inai; M. Shiotani; M. Fujiwara; F. Hasebe; H. Voemel
    Atmospheric Measurement Techniques, 8, 10, 4043, 4054, 2015年, [査読有り]
    英語, 研究論文(学術雑誌)
  • The occurrence of cirrus clouds associated with eastward propagating equatorialn = 0 inertio-gravity and Kelvin waves in November 2011 during the CINDY2011/DYNAMO campaign
    Suzuki Junko; Fujiwara Masatomo; Nishizawa Tomoaki; Shirooka Ryuichi; Yoneyama Kunio; Katsumata Masaki; Matsui Ichiro; Sugimoto Nobuo
    Journal of Geophysical Research: Atmospheres, 118, 23, 12, 12, American Geophysical Union, 2013年12月16日
    英語
  • The occurrence of cirrus clouds associated with eastward propagating equatorial n = 0 inertio-gravity and Kelvin waves in November 2011 during the CINDY2011/DYNAMO campaign
    Junko Suzuki; Masatomo Fujiwara; Tomoaki Nishizawa; Ryuichi Shirooka; Kunio Yoneyama; Masaki Katsumata; Ichiro Matsui; Nobuo Sugimoto
    Journal of Geophysical Research Atmospheres, 118, 23, 12941, 12947, Blackwell Publishing Ltd, 2013年12月16日, [査読有り]
    英語, 研究論文(学術雑誌)
  • Interpretation of the vertical structure and seasonal variation of the diurnal migrating tide from the troposphere to the lower mesosphere
    T. Sakazaki; M. Fujiwara; X. Zhang
    JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, 105, 66, 80, 2013年12月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Comparison of ozone profiles between Superconducting Submillimeter-Wave Limb-Emission Sounder and worldwide ozonesonde measurements
    Koji Imai; Masatomo Fujiwara; Yoichi Inai; Naohiro Manago; Makoto Suzuki; Takuki Sano; Chihiro Mitsuda; Yoko Naito; Fumio Hasebe; Takashi Koide; Masato Shiotani
    Journal of Geophysical Research Atmospheres, 118, 22, 12755, 12765, Blackwell Publishing Ltd, 2013年11月27日, [査読有り]
    英語, 研究論文(学術雑誌)
  • Validation of ozone data from the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES)
    Koji Imai; Naohiro Manago; Chihiro Mitsuda; Yoko Naito; Eriko Nishimoto; Takatoshi Sakazaki; Masatomo Fujiwara; Lucien Froidevaux; Thomas Von Clarmann; Gabriele P. Stiller; Donal P. Murtagh; Ping-Ping Rong; Martin G. Mlynczak; Kaley A. Walker; Douglas E. Kinnison; Hideharu Akiyoshi; Tetsu Nakamura; Takayuki Miyasaka; Toshiyuki Nishibori; Satoko Mizobuchi; Ken-Ichi Kikuchi; Hiroyuki Ozeki; Chikako Takahashi; Hiroo Hayashi; Takuki Sano; Makoto Suzuki; Masahiro Takayanagi; Masato Shiotani
    Journal of Geophysical Research Atmospheres, 118, 11, 5750, 5769, Blackwell Publishing Ltd, 2013年06月16日, [査読有り]
    英語, 研究論文(学術雑誌)
  • Correction of the Stepwise Change Observed at 0 degrees C in Meisei RS2-91, RS-01G, and RS-06G Radiosonde Relative Humidity Profiles
    Takuji Sugidachi; Masatomo Fujiwara
    JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN, 91, 3, 323, 336, 2013年06月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Ozone variations over the northern subtropical region revealed by ozonesonde observations in Hanoi
    S. Y. Ogino; M. Fujiwara; M. Shiotani; F. Hasebe; J. Matsumoto; Thuy Ha T. Hoang; Tan Thanh T. Nguyen
    Journal of Geophysical Research Atmospheres, 118, 8, 3245, 3257, Blackwell Publishing Ltd, 2013年04月27日, [査読有り]
    英語, 研究論文(学術雑誌)
  • Diurnal ozone variations in the stratosphere revealed in observations from the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on board the International Space Station (ISS)
    Takatoshi Sakazaki; Masatomo Fujiwara; Chihiro Mitsuda; Koji Imai; Naohiro Manago; Yoko Naito; Tetsu Nakamura; Hideharu Akiyoshi; Douglas Kinnison; Takuki Sano; Makoto Suzuki; Masato Shiotani
    Journal of Geophysical Research Atmospheres, 118, 7, 2991, 3006, Blackwell Publishing Ltd, 2013年04月16日, [査読有り]
    英語, 研究論文(学術雑誌)
  • Ozone variations over the northern subtropical region revealed by ozonesonde observations in Hanoi
    S. -Y. Ogino; M. Fujiwara; M. Shiotani; F. Hasebe; J. Matsumoto; Thuy Ha T. Hoang; Tan Thanh T. Nguyen
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 118, 8, 3245, 3257, 2013年04月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Validation of stratospheric and mesospheric ozone observed by SMILES from International Space Station
    Y. Kasai; H. Sagawa; D. Kreyling; E. Dupuy; P. Baron; J. Mendrok; K. Suzuki; T. O. Sato; T. Nishibori; S. Mizobuchi; K. Kikuchi; T. Manabe; H. Ozeki; T. Sugita; M. Fujiwara; Y. Irimajiri; K. A. Walker; P. F. Bernath; C. Boone; G. Stiller; T. von Clarmann; J. Orphal; J. Urban; D. Murtagh; E. J. Llewellyn; D. Degenstein; A. E. Bourassa; N. D. Lloyd; L. Froidevaux; M. Birk; G. Wagner; F. Schreier; J. Xu; P. Vogt; T. Trautmann; M. Yasui
    ATMOSPHERIC MEASUREMENT TECHNIQUES, 6, 9, 2311, 2338, 2013年, [査読有り]
    英語, 研究論文(学術雑誌)
  • Impact of a new temperature-dependence correction on historical meisei radiosonde humidity data
    Takuji Sugidachi; Masatomo Fujiwara
    Scientific Online Letters on the Atmosphere, 9, 1, 179, 182, 2013年, [査読有り]
    英語, 研究論文(学術雑誌)
  • Cold trap dehydration in the Tropical Tropopause Layer characterised by SOWER chilled-mirror hygrometer network data in the Tropical Pacific
    F. Hasebe; Y. Inai; M. Shiotani; M. Fujiwara; H. Voemel; N. Nishi; S. -Y. Ogino; T. Shibata; S. Iwasaki; N. Komala; T. Peter; S. J. Oltmans
    ATMOSPHERIC CHEMISTRY AND PHYSICS, 13, 8, 4393, 4411, 2013年, [査読有り]
    英語, 研究論文(学術雑誌)
  • On the use of the correction factor with Japanese ozonesonde data
    G. A. Morris; G. Labow; H. Akimoto; M. Takigawa; M. Fujiwara; F. Hasebe; J. Hirokawa; T. Koide
    ATMOSPHERIC CHEMISTRY AND PHYSICS, 13, 3, 1243, 1260, 2013年, [査読有り]
    英語, 研究論文(学術雑誌)
  • Dehydration in the tropical tropopause layer estimated from the water vapor match
    Y. Inai; F. Hasebe; M. Fujiwara; M. Shiotani; N. Nishi; S. Y. Ogino; H. Vömel; S. Iwasaki; T. Shibata
    Atmospheric Chemistry and Physics, 13, 17, 8623, 8642, Copernicus {GmbH}, 2013年, [査読有り]
    英語, 研究論文(学術雑誌)
  • Southern Hemisphere Additional Ozonesondes (SHADOZ) ozone climatology (2005-2009): Tropospheric and tropical tropopause layer (TTL) profiles with comparisons to OMI-based ozone products
    Anne M. Thompson; Sonya K. Miller; Simone Tilmes; Debra W. Kollonige; Jacquelyn C. Witte; Samuel J. Oltmans; Bryan J. Johnson; Masatomo Fujiwara; F. J. Schmidlin; G. J. R. Coetzee; Ninong Komala; Matakite Maata; Maznorizan Bt Mohamad; J. Nguyo; C. Mutai; S-Y. Ogino; F. Raimundo Da Silva; N. M. Paes Leme; Francoise Posny; Rinus Scheele; Henry B. Selkirk; Masato Shiotani; Rene Stuebi; Gilbert Levrat; Bertrand Calpini; Valerie Thouret; Haruo Tsuruta; Jessica Valverde Canossa; Holger Voemel; S. Yonemura; Jorge Andres Diaz; Nguyen T. Tan Thanh; Hoang T. Thuy Ha
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 117, 2012年12月, [査読有り]
    英語, 研究論文(学術雑誌)
  • High supersaturation inside cirrus in well-developed tropical tropopause layer over Indonesia
    Y. Inai; T. Shibata; M. Fujiwara; F. Hasebe; H. Voemel
    GEOPHYSICAL RESEARCH LETTERS, 39, 2012年10月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Analysis of the tropical tropopause layer using the Nonhydrostatic Icosahedral Atmospheric Model (NICAM): 2. An experiment under the atmospheric conditions of December 2006 to January 2007
    H. Kubokawa; M. Fujiwara; T. Nasuno; M. Miura; M. K. Yamamoto; M. Satoh
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 117, 2012年09月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Diurnal tides from the troposphere to the lower mesosphere as deduced from TIMED/SABER satellite data and six global reanalysis data sets
    T. Sakazaki; M. Fujiwara; X. Zhang; M. E. Hagan; J. M. Forbes
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 117, 2012年07月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Wave activity in the tropical tropopause layer in seven reanalysis and four chemistry climate model data sets
    M. Fujiwara; J. Suzuki; A. Gettelman; M. I. Hegglin; H. Akiyoshi; K. Shibata
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 117, 2012年06月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Cirrus cloud appearance in a volcanic aerosol layer around the tropical cold point tropopause over Biak, Indonesia, in January 2011
    T. Shibata; M. Hayashi; A. Naganuma; N. Hara; K. Hara; F. Hasebe; K. Shimizu; N. Komala; Y. Inai; H. Voemel; S. Hamdi; S. Iwasaki; M. Fujiwara; M. Shiotani; S-Y. Ogino; N. Nishi
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 117, 2012年06月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Southern Hemisphere Additional Ozonesondes (SHADOZ) ozone climatology (2005-2009): Tropospheric and tropical tropopause layer (TTL) profiles with comparisons to OMI-based ozone products
    Anne M. Thompson; Sonya K. Miller; Simone Tilmes; Debra W. Kollonige; Jacquelyn C. Witte; Samuel J. Oltmans; Bryan J. Johnson; Masatomo Fujiwara; F. J. Schmidlin; G. J.R. Coetzee; Ninong Komala; Matakite Maata; Maznorizan Bt Mohamad; J. Nguyo; C. Mutai; S. Y. Ogino; F. Raimundo Da Silva; N. M. Paes Leme; Francoise Posny; Rinus Scheele; Henry B. Selkirk; Masato Shiotani; René Stbi; Gilbert Levrat; Bertrand Calpini; Valérie Thouret; Haruo Tsuruta; Jessica Valverde Canossa; Holger Vmel; S. Yonemura; Jorge Andrés Diaz; Nguyen T. Tan Thanh; Hoang T. Thuy Ha
    Journal of Geophysical Research Atmospheres, 117, 23, Blackwell Publishing Ltd, 2012年, [査読有り]
    英語, 研究論文(学術雑誌)
  • Diurnal variations of upper tropospheric and lower stratospheric winds over Japan as revealed with middle and upper atmosphere radar (34.85 degrees N, 136.10 degrees E) and five reanalysis data sets
    T. Sakazaki; M. Fujiwara; H. Hashiguchi
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 115, 2010年12月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Multimodel assessment of the upper troposphere and lower stratosphere: Tropics and global trends
    A. Gettelman; M. I. Hegglin; S. -W. Son; J. Kim; M. Fujiwara; T. Birner; S. Kremser; M. Rex; J. A. Anel; H. Akiyoshi; J. Austin; S. Bekki; P. Braesike; C. Bruehl; N. Butchart; M. Chipperfield; M. Dameris; S. Dhomse; H. Garny; S. C. Hardiman; P. Joeckel; D. E. Kinnison; J. F. Lamarque; E. Mancini; M. Marchand; M. Michou; O. Morgenstern; S. Pawson; G. Pitari; D. Plummer; J. A. Pyle; E. Rozanov; J. Scinocca; T. G. Shepherd; K. Shibata; D. Smale; H. Teyssedre; W. Tian
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 115, 2010年10月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Seasonal to decadal variations of water vapor in the tropical lower stratosphere observed with balloon-borne cryogenic frost point hygrometers
    M. Fujiwara; H. Voemel; F. Hasebe; M. Shiotani; S-Y. Ogino; S. Iwasaki; N. Nishi; T. Shibata; K. Shimizu; E. Nishimoto; J. M. Valverde Canossa; H. B. Selkirk; S. J. Oltmans
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 115, 2010年09月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Diurnal Variations in Lower-Tropospheric Wind over Japan Part II: Analysis of Japan Meteorological Agency Mesoscale Analysis Data and Four Global Reanalysis Data Sets
    Takatoshi Sakazaki; Masatomo Fujiwara
    JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN, 88, 3, 349, 372, 2010年06月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Diurnal Variations in Lower-Tropospheric Wind over Japan Part I: Observational Results using the Wind Profiler Network and Data Acquisition System (WINDAS)
    Takatoshi Sakazaki; Masatomo Fujiwara
    JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN, 88, 3, 325, 347, 2010年06月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Analysis of the tropical tropopause layer using the Nonhydrostatic Icosahedral Atmospheric Model (NICAM): Aqua planet experiments
    H. Kubokawa; M. Fujiwara; T. Nasuno; M. Satoh
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 115, 2010年04月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Analysis of the tropical tropopause layer using the Nonhydrostatic Icosahedral Atmospheric Model (NICAM): Aqua planet experiments
    H. Kubokawa; M. Fujiwara; T. Nasuno; M. Satoh
    Journal of Geophysical Research Atmospheres, 115, 8, Blackwell Publishing Ltd, 2010年, [査読有り]
    英語, 研究論文(学術雑誌)
  • Cloud-Top Height Variability Associated with Equatorial Kelvin Waves in the Tropical Tropopause Layer during the Mirai Indian Ocean cruise for the Study of the MJO-Convection Onset (MISMO) Campaign
    Junko Suzuki; Masatomo Fujiwara; Atsushi Hamada; Yoichi Inai; Jun Yamaguchi; Ryuichi Shirooka; Fumio Hasebe; Toshiaki Takano
    SOLA, 6, 97, 100, 2010年, [査読有り]
    英語, 研究論文(学術雑誌)
  • Cirrus observations in the tropical tropopause layer over the western Pacific
    M. Fujiwara; S. Iwasaki; A. Shimizu; Y. Inai; M. Shiotani; F. Hasebe; I. Matsui; N. Sugimoto; H. Okamoto; N. Nishi; A. Hamada; T. Sakazaki; K. Yoneyama
    Journal of Geophysical Research Atmospheres, 114, 9, D09304, Blackwell Publishing Ltd, 2009年05月16日, [査読有り]
    英語, 研究論文(学術雑誌)
  • Cirrus observations in the tropical tropopause layer over the western Pacific
    M. Fujiwara; S. Iwasaki; A. Shimizu; Y. Inai; M. Shiotani; F. Hasebe; I. Matsui; N. Sugimoto; H. Okamoto; N. Nishi; A. Hamada; T. Sakazaki; K. Yoneyama
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 114, 2009年05月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Correction of Radiosonde Pressure and Temperature Measurements Using Simultaneous GPS Height Data
    Yoichi Inai; Fumio Hasebe; Kensaku Shimizu; Masatomo Fujiwara
    SOLA, 5, 109, 112, 2009年, [査読有り]
    英語, 研究論文(学術雑誌)
  • Diurnal Variations in Summertime Surface Wind upon Japanese Plains: Hodograph Rotation and Its Dynamics
    Takatoshi Sakazaki; Masatomo Fujiwara
    JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN, 86, 5, 787, 803, 2008年10月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Ozonesonde observations at Christmas Island (2*N, 157*W) in the equatorial central pacific
    Hisahiro Takashima; M. Shiotani; M. Fujiwara; N. Nishi; F. Hasebe
    Journal of Geophysical Research Atmospheres, 113, 10, Blackwell Publishing Ltd, 2008年05月27日, [査読有り]
    英語, 研究論文(学術雑誌)
  • Correlation between equatorial Kelvin waves and the occurrence of extremely thin ice clouds at the tropical tropopause
    F. Immler; K. Krueger; M. Fujiwara; G. Verver; M. Rex; O. Schrems
    ATMOSPHERIC CHEMISTRY AND PHYSICS, 8, 14, 4019, 4026, 2008年, [査読有り]
    英語, 研究論文(学術雑誌)
  • Correction for Radiation Dry Bias Found in RS92 Radiosonde Data during the MISMO Field Experiment
    Kunio Yoneyama; Mikiko Fujita; Naoki Sato; Masatomo Fujiwara; Yoichi Inai; Fumio Hasebe
    SOLA, 4, 13, 16, 2008年, [査読有り]
    英語, 研究論文(学術雑誌)
  • Validation of Aura Microwave Limb Sounder water vapor by balloon-borne Cryogenic Frost point Hygrometer measurements
    Holger Vömel; J. E. Barnes; R. N. Forno; M. Fujiwara; F. Hasebe; S. Iwasaki; R. Kivi; N. Komala; E. Kyrö; T. Leblanc; B. Morel; S. Y. Ogino; W. G. Read; S. C. Ryan; S. Saraspriya; H. Selkirk; M. Shiotani; J. Valverde Canossa; D. N. Whiteman
    Journal of Geophysical Research Atmospheres, 112, 24, Blackwell Publishing Ltd, 2007年12月27日, [査読有り]
    英語, 研究論文(学術雑誌)
  • Validation of Aura Microwave Limb Sounder Ozone by ozonesonde and lidar measurements
    Y. B. Jiang; L. Froidevaux; A. Lambert; N. J. Livesey; W. G. Read; J. W. Waters; B. Bojkov; T. Leblanc; I. S. McDermid; S. Godin-Beekmann; M. J. Filipiak; R. S. Harwood; R. A. Fuller; W. H. Daffer; B. J. Drouin; R. E. Cofield; D. T. Cuddy; R. F. Jarnot; B. W. Knosp; V. S. Perun; M. J. Schwartz; W. V. Snyder; P. C. Stek; R. P. Thurstans; P. A. Wagner; M. Allaart; S. B. Andersen; G. Bodeker; B. Calpini; H. Claude; G. Coetzee; J. Davies; H. De Backer; H. Dier; M. Fujiwara; B. Johnson; H. Kelder; N. P. Leme; G. König-Langlo; E. Kyro; G. Laneve; L. S. Fook; J. Merrill; G. Morris; M. Newchurch; S. Oltmans; M. C. Parrondos; F. Posny; F. Schmidlin; P. Skrivankova; R. Stubi; D. Tarasick; A. Thompson; V. Thouret; P. Viatte; H. Vömel; P. von Der Gathen; M. Yela; G. Zablocki
    Journal of Geophysical Research Atmospheres, 112, 24, Blackwell Publishing Ltd, 2007年12月27日, [査読有り]
    英語, 研究論文(学術雑誌)
  • A trajectory-based estimate of the tropospheric ozone column using the residual method
    M. R. Schoeberl; J. R. Ziemke; B. Bojkov; N. Livesey; B. Duncan; S. Strahan; L. Froidevaux; S. Kulawik; P. K. Bhartia; S. Chandra; P. F. Levelt; J. C. Witte; A. M. Thompson; E. Cuevas; A. Redondas; D. W. Tarasick; J. Davies; G. Bodeker; G. Hansen; B. J. Johnson; S. J. Oltmans; H. Vömel; M. Allaart; H. Kelder; M. Newchurch; S. Godin-Beekmann; G. Ancellet; H. Claude; S. B. Andersen; E. Kyrö; M. Parrondos; M. Yela; G. Zablocki; D. Moore; H. Dier; P. von der Gathen; P. Viatte; R. Stübi; B. Calpini; P. Skrivankova; V. Dorokhov; H. de Backer; F. J. Schmidlin; G. Coetzee; M. Fujiwara; V. Thouret; F. Posny; G. Morris; J. Merrill; C. P. Leong; G. Koenig-Langlo; E. Joseph
    Journal of Geophysical Research Atmospheres, 112, 24, Blackwell Publishing Ltd, 2007年12月27日, [査読有り]
    英語, 研究論文(学術雑誌)
  • Origin and transport of tropical cirrus clouds observed over Paramaribo, Suriname (5.8°N, 55.2°W)
    J. P.F. Fortuin; C. R. Becker; M. Fujiwara; F. Immler; H. M. Kelder; M. P. Scheele; O. Schrems; G. H.L. Verver
    Journal of Geophysical Research Atmospheres, 112, 9, Blackwell Publishing Ltd, 2007年05月16日, [査読有り]
    英語, 研究論文(学術雑誌)
  • Cirrus clouds, humidity, and dehydration in the tropical tropopause layer observed at Paramaribo, Suriname (5.8°N, 55.2°W)
    Franz Immler; Kirstin Krüger; Susann Tegtmeier; Masatomo Fujiwara; Paul Fortuin; Gé Verver; Otto Schrems
    Journal of Geophysical Research Atmospheres, 112, 3, Blackwell Publishing Ltd, 2007年02月16日, [査読有り]
    英語, 研究論文(学術雑誌)
  • Tropical cirrus clouds near cold point tropopause under ice supersaturated conditions observed by lidar and ballon-borne cryogenic frost point hygrometer
    Takashi Shibata; Holger Vömel; Saipul Hamdi; Sri Kaloka; Fumio Hasebe; Masatomo Fujiwara; Masato Shiotani
    Journal of Geophysical Research Atmospheres, 112, 3, Blackwell Publishing Ltd, 2007年02月16日, [査読有り]
    英語, 研究論文(学術雑誌)
  • In situ observations of dehydrated air parcels advected horizontally in the Tropical Tropopause Layer of the western Pacific
    F. Hasebe; M. Fujiwara; N. Nishi; M. Shiotani; H. Voemel; S. Oltmans; H. Takashima; S. Saraspriya; N. Komala; Y. Inai
    ATMOSPHERIC CHEMISTRY AND PHYSICS, 7, 803, 813, 2007年02月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Performance of the Vaisala RS80A/H and RS90 humicap sensors and the meteolabor "Snow white" chilled-mirror hygrometer in Paramaribo, Suriname
    Ge Verver; Masatomo Fujiwara; Pier Dolmans; Cor Becker; Paul Fortuin; Larry Miloshevich
    JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY, 23, 11, 1506, 1518, 2006年11月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Combined MU radar and ozonesonde measurements of turbulence and ozone fluxes in the tropo-stratosphere over Shigaraki, Japan
    NM Gavrilov; S Fukao; H Hashiguchi; K Kita; K Sato; Y Tomikawa; M Fujiwara
    GEOPHYSICAL RESEARCH LETTERS, 33, 9, 2006年05月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Correlations and emission ratios among bromoform, dibromochloromethane, and dibromomethane in the atmosphere
    Y. Yokouchi; F. Hasebe; M. Fujiwara; H. Takashima; M. Shiotani; N. Nishi; Y. Kanaya; S. Hashimoto; P. Fraser; D. Toom-Sauntry; H. Mukai; Y. Nojiri
    Journal of Geophysical Research Atmospheres, 110, 23, 1, 9, Blackwell Publishing Ltd, 2005年12月16日, [査読有り]
    英語, 研究論文(学術雑誌)
  • New Characteristics of the Tropical Tropopause Revealed by CHAMP/GPS Measurements
    M. Venkat Ratnam; T. Tsuda; M. Shiotani; M. Fujiwara
    SOLA, 1, 185, 188, 2005年, [査読有り]
    英語, 研究論文(学術雑誌)
  • Radiation balance of the tropical tropopause layer
    A Gettelman; PMD Forster; M Fujiwara; Q Fu; H Vomel; LK Gohar; C Johanson; M Ammerman
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 109, D7, 2004年04月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Upper-tropospheric inversion and easterly jet in the tropics
    M Fujiwara; SP Xie; M Shiotani; H Hashizume; F Hasebe; H Vomel; SJ Oltmans; T Watanabe
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 108, D24, 2003年12月, [査読有り]
    英語, 研究論文(学術雑誌)
  • The behavior of the Snow White chilled-mirror hygrometer in extremely dry conditions
    H Vomel; M Fujiwara; M Shiotani; F Hasebe; SJ Oltmans; JE Barnes
    JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY, 20, 11, 1560, 1567, 2003年11月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Performance of the meteolabor ''Snow White'' chilled-mirror hygrometer in the tropical troposphere: Comparisons with the Vaisala RS80 A/H-Humicap sensors
    M Fujiwara; M Shiotani; F Hasebe; H Vomel; SJ Oltmans; PW Ruppert; T Horinouchi; T Tsuda
    JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY, 20, 11, 1534, 1542, 2003年11月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Kelvin-Helmholtz instability around the tropical tropopause observed with the Equatorial Atmosphere Radar
    MK Yamamoto; M Fujiwara; T Horinouchi; H Hashiguchi; S Fukao
    GEOPHYSICAL RESEARCH LETTERS, 30, 9, 2003年05月, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌)
  • Turbulence at the tropopause due to breaking Kelvin waves observed by the Equatorial Atmosphere Radar
    M Fujiwara; MK Yamamoto; H Hashiguchi; T Horinouchi; S Fukao
    GEOPHYSICAL RESEARCH LETTERS, 30, 4, 2003年02月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Reply to comment by A. E. Dessler and E. M. Weinstock on "Balloon-borne observations of water vapor and ozone in the tropical upper troposphere and lower stratosphere" by H. Vomel et al.
    H Vomel; SJ Oltmans; BJ Johnson; F Hasebe; M Shiotani; M Fujiwara; N Nishi; M Agama; J Cornejo; F Paredes; Enriquez, II
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 108, D4, 2003年02月, [査読有り]
    英語
  • Southern Hemisphere Additional Ozonesondes (SHADOZ) 1998-2000 tropical ozone climatology - 2. Tropospheric variability and the zonal wave-one
    AM Thompson; JC Witte; SJ Oltmans; FJ Schmidlin; JA Logan; M Fujiwara; VWJH Kirchhoff; F Posny; GJR Coetzee; B Hoegger; SJ Kawakami; T Ogawa; JPF Fortuin; HM Kelder
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 108, D2, 2003年01月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Southern Hemisphere Additional Ozonesondes (SHADOZ) 1998-2000 tropical ozone climatology - 1. Comparison with Total Ozone Mapping Spectrometer (TOMS) and ground-based measurements
    AM Thompson; JC Witte; RD McPeters; SJ Oltmans; FJ Schmidlin; JA Logan; M Fujiwara; VWJH Kirchhoff; F Posny; GJR Coetzee; B Hoegger; S Kawakami; T Ogawa; BJ Johnson; H Vomel; G Labow
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 108, D2, 2003年01月, [査読有り]
    英語, 研究論文(学術雑誌)
  • 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 Kelana; B Suhardi; SWB Harijono; M Kudsy; T Sribimawati; MD Yamanaka
    ATMOSPHERIC ENVIRONMENT, 37, 3, 353, 362, 2003年01月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Direct observations of atmospheric boundary layer response to SST variations associated with tropical instability waves over the eastern equatorial Pacific
    H Hashizume; SP Xie; M Fujiwara; M Shiotani; T Watanabe; Y Tanimoto; WT Liu; K Takeuchi
    JOURNAL OF CLIMATE, 15, 23, 3379, 3393, 2002年12月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Ozonesonde observations in the equatorial eastern Pacific - the Shoyo-Maru survey
    M Shiotani; M Fujiwara; F Hasebe; H Hashizume; H Vomel; SJ Oltmans; T Watanabe
    JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN, 80, 4B, 897, 909, 2002年09月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Balloon-borne observations of water vapor and ozone in the tropical upper troposphere and lower stratosphere
    H Vomel; SJ Oltmans; BJ Johnson; F Hasebe; M Shiotani; M Fujiwara; N Nishi; M Agama; J Cornejo; F Paredes; H Enriquez
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 107, D14, 2002年07月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Relationship between wind and precipitation observed with a UHF radar, GPS rawinsondes and surface meteorological instruments at Kototabang, West Sumatera during September-October 1998
    F Murata; MD Yamanaka; M Fujiwara; SY Ogino; H Hashiguchi; S Fukao; M Kudsy; T Sribiawati; SWB Harijono; E Kelana
    JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN, 80, 3, 347, 360, 2002年06月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Formation of an ozone lamina due to differential advection revealed by intensive observations
    Y Tomikawa; K Sato; K Kita; M Fujiwara; M Yamamori; T Sano
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 107, D10, 2002年05月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Role of the equatorial Kelvin wave in stratosphere-troposphere exchange in a general circulation model
    M Fujiwara; M Takahashi
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 106, D19, 22763, 22780, 2001年10月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Water vapor control at the tropopause by equatorial Kelvin waves observed over the Galapagos
    M Fujiwara; F Hasebe; M Shiotani; N Nishi; H Vomel; SJ Oltmans
    GEOPHYSICAL RESEARCH LETTERS, 28, 16, 3143, 3146, 2001年08月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Tropical tropospheric ozone and biomass burning
    AM Thompson; JC Witte; RD Hudson; H Guo; Herman, JR; M Fujiwara
    SCIENCE, 291, 5511, 2128, 2132, 2001年03月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Seasonal variation of tropospheric ozone in Indonesia revealed by 5-year ground-based observations
    Masatomo Fujiwara; Kazuyuki Kita; Toshihiro Ogawa; Shuji Kawakami; Takuki Sano; Ninong Komala; Slamet Saraspriya; Agus Suripto
    Journal of Geophysical Research Atmospheres, 105, 2, 1879, 1888, Blackwell Publishing Ltd, 2000年, [査読有り]
    英語, 研究論文(学術雑誌)
  • 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, 389-390, 2000年
    英語, 研究論文(国際会議プロシーディングス)
  • 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, 427-428, 2000年
    英語, 研究論文(国際会議プロシーディングス)
  • 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, 95-96, 2000年
    英語, 研究論文(国際会議プロシーディングス), Proceedings of Quadrennial Ozone Symposium Sapporo 2000
  • Total ozone increase associated with forest fires over the Indonesian region and its relation to the El Nino-Southern oscillation
    K Kita; M Fujiwara; S Kawakami
    ATMOSPHERIC ENVIRONMENT, 34, 17, 2681, 2690, 2000年, [査読有り]
    英語, 研究論文(学術雑誌)
  • 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
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 105, D2, 1879, 1888, 2000年01月, [査読有り]
    英語, 研究論文(学術雑誌)
  • 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; A Suripto
    GEOPHYSICAL RESEARCH LETTERS, 26, 16, 2417, 2420, 1999年08月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Stratosphere-troposphere exchange of ozone associated with the equatorial Kelvin wave as observed with ozonesondes and rawinsondes
    M Fujiwara; K Kita; T Ogawa
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 103, D15, 19173, 19182, 1998年08月, [査読有り]
    英語, 研究論文(学術雑誌)
  • 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, 45-46, 1998年
    英語, 研究論文(国際会議プロシーディングス)
■ その他活動・業績
■ 書籍等出版物
  • 成層圏・対流圏を巡る大気, 気象研究ノート, 第250号
    長谷部文雄; 青木周司; 柴田隆, 編, 7.2 人工衛星による大気観測
    日本気象学会, 2025年, 154, 学術書, [分担執筆]
  • Field measurements for passive environmental remote sensing : instrumentation, intensive campaigns, and satellite applications
    Hurst, D. F; M. Fujiwara; S. Oltmans (Nalli, Nicholas R. ed.), Chapter 3. Frost point hygrometers
    Elsevier, 2022年, 9780128239537, xv, 436 p., 18, 英語, [国際共著], [査読有り], [共著]
  • SPARC Reanalysis Intercomparison Project (S-RIP) Final Report
    Masatomo Fujiwara; Gloria L. Manney; Lesley J. Gray; Jonathon S. Wright, Co-editor, Chapters 1, 2, 3, 4, 8, 9, 11, 12
    WCRP/SPARC, 2022年01月, 612, 英語, 学術書, [査読有り], [共編者(共編著者)]
  • Handbook of Atmospheric Measurements
    Vömel, H; M. Fujiwara, Chapter 46. Aerological measurements
    edited by Thomas Foken, Springer Nature, Switzerland, 2021年, 1247-1280, 英語, 学術書, [国際共著], [査読有り], [共著]
  • 低温環境の科学事典
    河村公隆; 大島慶一郎; 小達恒夫; 川村賢二; 佐﨑元; 杉山慎; 関宰; 高橋晃周; 西岡純; 原登志彦; 福井学; 藤吉康志; 三寺史夫; 宮﨑雄三; 本山秀明; 渡部直樹, ブリューワー-ドブソン循環(成層圏の大気大循環)
    朝倉書店, 2016年, [分担執筆]
  • 第2版 地球惑星科学入門
    在田一則; 竹下徹; 見延庄士郎; 渡部重十, 第18章共同執筆
    北海道大学出版会, 2015年, [分担執筆]
  • 地球と宇宙の化学事典
    日本地球化学会, 成層圏大気の組成
    朝倉書店, 2012年, [分担執筆]
  • 地球惑星科学入門
    在田一則; 竹下徹; 見延庄士郎; 渡部重十, 第18章共同執筆
    北海道大学出版会, 2010年, [分担執筆]
  • オゾン層破壊の科学
    北海道大学大学院環境科, 序章, 1章, 5-1章, 5-2章, 終章
    北海道大学出版会, 2007年, 9784832981799, [分担執筆]
■ 講演・口頭発表等
■ 主な担当授業
  • 大気海洋物理学基礎論, 2024年, 修士課程, 環境科学院
  • 一般教育演習(フレッシュマンセミナー), 2024年, 学士課程, 全学教育
■ 所属学協会
  • 日本地球惑星科学連合
  • 日本大気化学会
  • American Meteorological Society
  • 日本気象学会
  • American Geophysical Union
■ 共同研究・競争的資金等の研究課題
  • フンガ・トンガ=フンガ・ハアパイ海底火山噴火の気候とオゾン層へのインパクト
    科学研究費補助事業
    2024年04月 - 2028年03月
    藤原正智
    日本学術振興会, 基盤研究(B), 北海道大学, 24K00700
  • 赤道大気レーダー・HYFLITSゾンデ観測による大気乱流・巻雲変動の解明
    科学研究費助成事業
    2024年04月 - 2027年03月
    Luce Hubert; 藤原 正智; 橋口 浩之
    日本学術振興会, 基盤研究(B), 京都大学, 24K03091
  • エルニーニョ・南方振動気候モデル実験による重力波と赤道準2年振動の新知見
    科学研究費助成事業
    2022年04月01日 - 2026年03月31日
    河谷 芳雄; 藤原 正智; 渡辺 真吾
    赤道準2年振動(QBO)気候モデル国際比較プロジェクト(QBOi)のco-leadsとして、国際共同研究を主導した。その中で現在進めているENSO-QBO実験を主責任者として取り纏め、3つの研究グループに分けて解析を続けて初期結果が出てきた。エルニーニョ実験とラニーニャ実験を比較すると、どの気候モデルもエルニーニョ実験の方がQBO周期が短く、観測と整合的である。しかし周期の変調にはモデル間で大きなばらつきがあり、その原因を運動量収支解析により調べている。
    典型的なQBO東西風サイクルが観測された1980年7月から1983年6月の36か月間を対象に、大気大循環モデルを全球再解析データを用いて初期値化したのち、月初から月末まで1か月間のTranspose-AMIP実験を毎月実施することにより、様々なQBO位相におけるQBO東西風の誤差成長の様子を調べた。使用した大気大循環モデルの弱点として、QBO東風シアー層の下降時の下降速度を過小評価する傾向が見られた。運動量収支の解析結果とともに、関連する国際会議で発表した。
    本年度は、4種の再解析データから計算した変形オイラー平均(TEM)方程式系の全項と残差項およびその全変数について、それらの気候値の比較・検証をおこなった論文を執筆し、Atmospheric Chemistry and Physics誌に投稿した。また、国際的な再解析データ比較検証活動S-RIP Phase 2の計画立案に関わりつつ、国際会議および国内学会にてこれに関連する招待講演をおこなった。また、基準高層観測網(GRUAN)の会議に出席し、ラジオゾンデ観測がQBOの状態監視の鍵であることについて議論した。
    日本学術振興会, 基盤研究(B), 23K22574
  • エルニーニョ・南方振動気候モデル実験による重力波と赤道準2年振動の新知見
    科学研究費助成事業
    2022年04月01日 - 2026年03月31日
    河谷 芳雄; 藤原 正智; 渡辺 真吾
    日本学術振興会, 基盤研究(B), 国立研究開発法人海洋研究開発機構, 22H01303
  • 気候変動における火山噴火影響と自然変動シグナルの同定と分離
    科学研究費助成事業
    2023年03月08日 - 2025年03月31日
    藤原 正智; DOGAR MUHAMMAD
    Dr. Dogar has analyzed data from his ensemble numerical experiments using the Geophysical Fluid Dynamics Laboratory (GFDL)'s coupled atmosphere-ocean climate model (GFDL-CM2.1) run on the Hokkaido University's high-performance supercomputing facility in the previous year. Dr. Dogar has written up a journal paper manuscript titled "ENSO and NAO Linkage to Strong Volcanism and Associated Post-Volcanic High-Latitude Winter Warming", which has been published in Geophysical Research Letter in January 2024. The main message of the paper is, "Our simulations strongly suggest that the post-eruption Eurasian winter warming is caused by a post-eruption positive NAO phase and not by coexisting ENSO-preconditioned variability." Furthermore, using the same simulation data set, Dr. Dogar has written up another manuscript titled "Volcanic Whispers: Decoding Post-eruption Winter Cooling Mysteries in the Middle East and North Africa - Unraveling ENSO and NAO Dynamics" and submitted it to another journal.
    Dr. Dogar attended the American Geophysical Union (AGU) Fall Meeting 2023 in December 2023 and the US CLIVAR's Workshop on Confronting Earth System Model Trends with Observations: The Good, the Bad, and the Ugly and presented these works there.
    日本学術振興会, 特別研究員奨励費, 北海道大学, 22KF0010
  • 春季東南アジアにおける大気汚染の発生機構: コールドサージに伴うオゾン変動の解明
    科学研究費助成事業
    2022年04月01日 - 2025年03月31日
    荻野 慎也; 藤原 正智
    日本学術振興会, 基盤研究(C), 国立研究開発法人海洋研究開発機構, 22K12367
  • 気候変動における火山噴火影響と自然変動シグナルの同定と分離
    科学研究費助成事業
    2022年04月22日 - 2024年03月31日
    藤原 正智; DOGAR MUHAMMAD
    日本学術振興会, 特別研究員奨励費, 北海道大学, 22F22012
  • エルニーニョ・南方振動に伴う重力波及び成層圏準2年振動の変調
    科学研究費助成事業
    2018年04月01日 - 2022年03月31日
    河谷 芳雄; 藤原 正智; 高薮 縁; 渡辺 真吾
    重力波パラメタリゼーションを組み込まない気候モデルを用いてエルニーニョ南方振動(ENSO)-赤道準2年振動(QBO)実験を行い、各種観測データ・再解析データを相補的に組み合わせ、ENSOに伴うQBOの変調メカニズムを調べた。重力波がエルニーニョ期に多く励起され、特に下部成層圏QBO位相の下降速度を早めていた。エルニーニョ期ではラニーニャ期に比べ、QBO下降を妨げる赤道上昇流が大きいものの、重力波の効果がより大きいため、周期が短くなることが分かった。重力波パラメタリゼーションを組み込んだモデルでは、重力波活動の変化が考慮されないため、上述したQBO変調は見られなかった。
    日本学術振興会, 基盤研究(B), 国立研究開発法人海洋研究開発機構, 18H01286
  • 過去の大規模火山噴火にともなう気候変動の研究
    科学研究費助成事業
    2016年04月01日 - 2020年03月31日
    藤原 正智
    20世紀後半の3つの大規模火山噴火(1963年アグン山、1982年エル・チチョン山、1991年ピナトゥボ山)それぞれについて、地表気温の応答および成層圏の循環の応答を、重回帰分析の手法を用いて明らかにした。この解析に使用した全球大気再解析データは、現在世界で10種以上存在しており、自らが2011年に提案・開始した国際的な総合的比較検証プロジェクト(S-RIP)も同時に推進し、データの品質評価もおこなった。3つの火山噴火事例に対して、地表気温は1年程度全球で概ね低下したが、過去の研究では過大評価であることが分かった。成層圏循環の応答は、3つの火山噴火で大きく異なることが明らかとなった。
    日本学術振興会, 基盤研究(C), 北海道大学, 16K05548
  • 衛星観測・大気再解析データの相互比較による堅牢な成層圏大気像の描出
    科学研究費助成事業
    2015年04月01日 - 2019年03月31日
    坂崎 貴俊; 塩谷 雅人; 藤原 正智; ハミルトン ケビン
    成層圏大気(高度10-50 kmの領域)は,地球の気候変動の理解に不可欠である一方直接観測が難しい.本研究では,特に日周期成分に注目し、複数の衛星リモートセンシングデータと大気再解析データ(数値シミュレーションと観測を融合(データ同化)させて得られる大気場の推定値)を相互比較することで,“最も確からしい描像はどれか?”を調べた.その結果,日周期の中でも特定のモードにのみ観測-再解析の差が顕れること、衛星観測データを無条件に信じることは危険であること、大気再解析データでは衛星観測の同化の影響が(上空ほど)大きいこと,が明らかになった.
    日本学術振興会, 若手研究(B), 京都大学, 15K17761
  • 熱帯対流圏界層内大気科学過程に関する力学的・化学的描像の統合
    科学研究費助成事業
    2014年05月30日 - 2019年03月31日
    長谷部 文雄; 青木 周司; 西 憲敬; 藤原 正智; 宮崎 和幸; 塩谷 雅人; 林 政彦; 柴田 隆; 荻野 慎也; 菅原 敏; 石戸谷 重之; 稲飯 洋一
    気候強制に対する成層圏の応答の解明を目的に、熱帯西部太平洋域においてSOWER・クライオサンプリング統合観測を実施し、成層圏大気の輸送過程を記述する独立3変数(水蒸気混合比、大気の年齢、重力分離)を含む諸量の高度分布を得た。その結果を後方流跡線や数値シミュレーションにより解析した結果、当初の目標を超え、観測データ相互の矛盾のない理解を導くような多くの知見を得た。熱帯対流圏界層・成層圏を対象にSOWER観測で蓄積してきたオゾン・水蒸気・雲粒子などのゾンデ観測で得られた知見は、夏季アジアモンスーン循環に伴う大気物質流出過程の研究へと継承・発展させられようとしている。
    日本学術振興会, 基盤研究(S), 北海道大学, 26220101
  • 気候変動に伴う赤道準2年振動の変化メカニズムの解明
    科学研究費助成事業
    2014年04月01日 - 2018年03月31日
    河谷 芳雄; 宮崎 和幸; 藤原 正智; 渡辺 真吾; 佐藤 薫
    非定常重力波パラメタリゼーションを用いない気候モデルで赤道準2年振動(QBO)と半年振動(SAO)を再現した。成層圏水蒸気の年々変動メカニズムを、最新衛星観測と気候モデルを組み合わせて解明し、論文として発表した。また気候変動に伴うQBO変化に関する実験を国際プロジェクトの枠組みの中で行い、QBO変化の特徴を調べた。
    成層圏再解析比較プロジェクト(S-RIP)に参加し、赤道域成層圏東西風に関して再解析間の類似・相違点を明らかにした研究、成層圏の平均子午面循環と混合の強度を比較した研究、力学場の季節変動や年々変動を比較した研究等を、複数の論文として発表した。
    日本学術振興会, 基盤研究(B), 国立研究開発法人海洋研究開発機構, 26287117
  • 対流圏界面観測用超小型タンデム気球の開発
    科学研究費助成事業
    2014年04月01日 - 2017年03月31日
    齋藤 芳隆; 藤原 正智; 山田 和彦
    本研究の目的は、日昇、日没時に対流圏界面を上下に移動しながら数週間に渡り飛翔し続ける気球実験システムを開発することにあった。体積100立方メートルの小型ゼロプレッシャー気球と体積10立方メートルのスーパープレシャー気球を連結したタンデム気球システムで実現できることを定量的に示し、最重要要素である気球開発、および、見通し限界の制限のない衛星通信システムの構築を行った。最終的には、体積10立方メートルで3kgと非常に軽い気球で、10,000 Paの耐圧性能を達成し、ガス漏れが十分小さいことを確認すると共に、イリジウム衛星を用いた小型通信システムを構築する成果をあげた。
    日本学術振興会, 挑戦的萌芽研究, 国立研究開発法人宇宙航空研究開発機構, 26630448
  • 熱帯対流圏界層内統合観測による「巻雲粒子個数濃度パラドックス」の解明
    科学研究費助成事業
    2014年04月01日 - 2015年03月31日
    長谷部 文雄; 藤原 正智; 塩谷 雅人; 林 政彦; 柴田 隆
    消耗品の購入と学会参加等の活動を開始したが、基盤研究(S)に採択されたため、経費を返還し事業を廃止する。
    日本学術振興会, 基盤研究(A), 北海道大学, 26247077
  • 気候監視のための高層気象観測用・超小型・高精度水蒸気センサーの開発
    科学研究費助成事業
    2010年 - 2012年
    藤原 正智
    気候監視を目的とした、地表から成層圏の水蒸気を高精度に測定できるラジオゾンデ用ペルチェ冷却方式鏡面冷却式露点計を開発した。また、現業用ラジオゾンデRS-06Gに搭載された高分子膜相対湿度計の系統的誤差の補正、及び水蒸気の液相・固相である雲粒子を測定できる雲ゾンデの開発に取り組んだ。これらの測定システムによって、従来の水蒸気測定に比べ信頼性・安定性に優れた大気中の水蒸気の測定が可能になる。
    日本学術振興会, 若手研究(B), 北海道大学, 22740306
  • 大気微量成分観測と4次元同化場解析による熱帯対流圏界層内脱水過程の解明
    科学研究費助成事業
    2009年 - 2012年
    長谷部 文雄; 塩谷 雅人; 藤原 正智; 西 憲敬; 荻野 慎也; 宮崎 和幸; 柴田 隆; 山崎 孝治; 岩崎 俊樹
    ゾンデを用いた現場観測により熱帯成層圏水蒸気量の長期トレンドを明らかにするとともに、熱帯対流圏界層(TTL)内を水平移流しながら巻雲を形成し凝結脱水中の大気の対氷過飽和度が80%に達する事例を見出した。また、観測された大気の水蒸気混合比とその大気の流跡線に沿って上流へ遡ることにより評価される最小飽和水蒸気混合比との比較解析により、TTL内を水平移流しながらゆっくり上昇する大気に働く脱水過程の観測的記述に初めて成功した。
    日本学術振興会, 基盤研究(A), 北海道大学, 21244072
  • 大気化学-気候結合モデルを用いた熱帯対流圏界面領域における輸送・光化学過程の研究
    科学研究費助成事業
    2007年 - 2009年
    藤原 正智
    熱帯の対流圏界面領域の気温や風速等には、数日から数十日の時間スケールで非常に大きな変動がある。これは主として熱帯の組織化した積雲群から励起される各種赤道波や季節内振動である。これら熱帯圏界面擾乱は、成層圏対流圏間の輸送過程や成層圏水蒸気濃度決定過程に主要な役割を果たしていると考えられる。したがって、成層圏オゾンの将来予測をおこなう数値モデル(大気化学-気候結合モデル、Chemistry Climate Model)は、こうした擾乱活動度を適切に表現している必要がある。本研究では、世界の4機関のCCM(CCSRNIES, CMAM, MRI, WACCM)と5つの全球再解析データ(ERA40, ERA-Interim, JRA25, NCEP/NCAR (NCEP1), NCEP-DEO AMIP-II (NCEP2))について、熱帯100hPaの気温・水平風速における波動活動度を、赤道対称-非対称分解による時空間スペクトル解析により調べ、比較した。
    全てのデータセットについて、赤道ケルビン波、混合ロスビー重力波が見い出された。いわゆる季節内振動(振動数0.05cycle/day以下)は、今回の手法ではほとんど統計的に有意なシグナルとしては取り出せなかったが、全てのデータセットにおいてこの振動数領域が最も大きなパワーを持っていた。気温データにおける、赤道ケルビン波、混合ロスビー重力波、季節内振動(赤道対称・東進のみ)について、パワースペクトル密度の領域積分として活動度を定義し、9つのデータセット間で比較した。その際赤道ケルビン波と混合ロスビー重力波については統計的有意性を考慮した。一方、季節内振動の活動度は上限値である。その結果、まず5種の全球再解析データ間で波動・擾乱活動度に大きな違いがあることが判明した。ERA40/ERA-Interimにおける赤道ケルビン波と混合ロスビー重力波の活動度は、NCEP1/NCEP2の2-3倍であり、JRA25はそれらの中間に位置する。季節内振動の活動度(の上限値)については、全球再解析データ間で大きな違いはない。一方、4種のCCMは基本的には全球再解析データ間のばらつきの範囲内に収まっていた。WACCMは赤道ケルビン波と混合ロスビー重力波の活動度が最大で、ERA40/ERA-Interimのそれと同程度であった。CCSRNIESは赤道ケルビン波活動度が最小で、MRIは混合ロスビー重力波活動度が最小であった。季節内振動の活動度については、CCSRNIES以外のCCMはいずれも全球再解析データよりも大きかった。
    つまり、CCMの検証をおこなうべき全球再解析データに大きなばらつきがあり、現実がどの程度なのか現在利用可能な全球再解析データの範囲では判断がつかないということが分かった。今後、ラジオゾンデデータやGPS掩蔽による気温データなどの観測データに立ち返って、現実の波動・擾乱活動度を調べる必要がある。
    日本学術振興会, 若手研究(B), 北海道大学, 19740283
  • 成層圏における水蒸気収支の定量化
    科学研究費助成事業
    2007年 - 2008年
    塩谷 雅人; 河本 望; 藤原 正智
    成層圏における熱バランスやオゾン化学に対して決定的な影響を与える水蒸気の変動について調べた. 特に熱帯域に注目して, いくつかの衛星観測データと定点観測ながら精度の高い水蒸気ゾンデデータとの比較・検討をおこない, 衛星観測のデータ質についての知見を得た. さらに, 熱帯下部成層圏における水蒸気混合0比の過去約15年にわたる年々変動について見たところ, さまざまな変動要因は存在するものの, 全体としては増加傾向を示すことがわかった.
    日本学術振興会, 基盤研究(C), 京都大学, 19540461
  • TC4と連携したゾンデ観測とモデリングによる熱帯対流圏界層内脱水過程の解明
    科学研究費助成事業
    2006年 - 2007年
    長谷部 文雄; 塩谷 雅人; 藤原 正智; 西 憲敬; 柴田 隆; 岩崎 俊樹
    熱帯対流圏界層(TTL)内脱水過程を解明し、熱帯成層圏水蒸気の長期トレンドを高精度ゾンデ観測により検出するために、TTL水蒸気量と水平移流に伴う大気の温度履歴との対応を、同一大気塊の複数回観測(match観測)により明らかにすることが本課題の特徴である。これまで蓄積してきた観測データから、ゾンデ観測された水蒸気混合比と移流する大気塊の経験する最小飽和水蒸気混合比との間には、観測点の立地条件、温位高度、季節、ENSOなどの気象条件に特有の脱水効率依存性が見出された。また、個々のゾンデ観測ごとに様々な高度で描かれた後方流跡線により大気塊の起源を求めたところ、相対湿度のジャンプが観測された高度の上下で流跡線が大きく配置を変える例が見出された。この結果は、ゾンデ観測された個々の大気塊ごとに、その大気質の変遷を大気塊の起源と対応させて議論することが可能であることを示す客観的根拠となり、水蒸気matchの信頼性を担保する事実と考えられる。個々の水蒸気分布の特徴をライダー観測された巻雲粒子の存在と対応させたところ、両者に良い対応の認められる例が見出された。これらの結果は、独自に開催した国際研究集会やアメリカ気象学会中層大気会議などの国際会議で発表し、投稿論文を準備中である。米国の予算削減に伴いTC4が中米に場を代えて実施されたため、TC4との同時観測は実現しなかったが、我々の観測データは人工衛星データの検証においても大いに貢献している。さらに、今後の発展を展望した試みとして、Lymana水蒸気計などの飛揚も行った。また、GCMに全球解析場や観測データを同化することにより流跡線解析を精密化する試みを開始した。こうした活動は、熱帯上部対流圏・下部成層圏における水蒸気の長期モニタリングの継続の重要性とともに、脱水過程に関する研究の発展の方向性を示すものである。
    日本学術振興会, 基盤研究(A), 北海道大学, 18204041
  • 熱帯域上部対流圏における巻雲の観測的研究
    科学研究費助成事業
    2004年 - 2006年
    深尾 昌一郎; 山本 真之; 西 憲敬; 岡本 創; 熊谷 博; 大野 裕一; 橋口 浩之; 中村 卓司; 藤原 正智
    熱帯域の上部対流圏に発生する巻雲は、熱帯大気の放射収支に大きな影響を与えるが、その発達・維持・消失のメカニズムは未解明の部分が多い。本研究課題では、大気の上下方向の運動(鉛直流)の観測が可能堰VHF帯ドップラーレーダー・巻雲内の氷粒子の落下速度の観測が可能なミリ波帯ドップラーレーダー・粒径の非常に小さい巻雲内の氷粒の観測が可能なレーザーレーダー(ライダー)・降水雲の観測が可能な気象レーダー・温度や水蒸気の観測が可能な気球(ラジオゾンデ)の観測データを用いて、熱帯域上部対流圏における巻雲の観測キャンペーンを実施するとともに、詳細なデータ解析を実施した。
    本研究課題の実施により、巻雲内の鉛直流が巻雲内の氷粒子の落下速度に与える影響、巻雲の発達・維持・消失に重要な役割を果たす熱帯域中上部対流圏の鉛直流の時間高度変動、巻雲の発生源である降水システム内での鉛直流変動を明らかにするとともに、研究成果を査読付き英文学術論文誌に発表した。また、研究成果を国内学会(気象学会、地球電磁気・地球惑星圏学会、大気圏シンポジウム、赤道大気上下結合公開ワークショップなど)で公表するとともに、国際学会(International Symposium on Coupling Processes in the Equatorial Atmosphere, Eleventh International Workshop on Technical and Scientific Aspects of MST Radar, The Third International SOWER Meetingなど)で発表した。本研究課題で得た研究成果の発展と観測データの活月により、巻雲の発達・維持・消失に関連した諸過程の解明に向けた新展開が期待される。
    日本学術振興会, 基盤研究(B), 京都大学, 16340139
  • 船舶からの水蒸気ゾンデ観測による熱帯西太平洋対流圏界面領域での脱水過程の解明
    科学研究費助成事業
    2004年 - 2005年
    藤原 正智
    2004年12月から2005年1月にかけて実施した海洋研究開発機構の海洋地球研究船「みらい」における水蒸気・オゾンゾンデ観測のデータ、および、同時期のキリバス、インドネシア、ベトナムにおける水蒸気・オゾンゾンデ観測のデータを解析した。流跡線解析の手法を用いて、観測点間における同一空気塊の変質を抽出することを試みた。流跡解析の結果、全38回の観測中、8つの観測ペアーにおいて、同一空気塊を観測していることが判明し、水蒸気濃度変化およびオゾン濃度変化について考察した。しかし、期待していた脱水(水蒸気減少)を示したペアーは1例しかなく、確定的な議論は出来なかった。今後の課題として、水蒸気センサーの精度のさらなる向上、流跡線計算の妥当性・現実性の検証、観測ペアー数の増大などの必要性が分かった。
    「みらい」においては、ミー散乱ライダーによる上層雲等の連続観測および3時間おきのラジオゾンデ観測も実施されたので、これらのデータを用いて、圏界面付近を東進する大規模な擾乱に伴う圏界面領域の雲粒子(脱水過程に伴う生成物)の変動についてデータ解析を行った。東進擾乱の寒偏差が「みらい」上空にやってくると、圏界面領域内に雲粒子が出現した。しかし、寒偏差が去った後も引き続き雲粒子が観測され、しかも夜間に数kmに渡って降下するという顕著な日変化が見い出された。さらに、ライダーの偏光解消度などの情報から、対流圏界面領域の雲と高度12km付近の雲とでは、雲物理学的性質が顕著に異なることも見い出された。大規模東進擾乱に伴う熱帯対流圏界面付近の雲粒子変動については、数年前に他のグループによる簡単な報告があるのみで、今回はじめて詳細な変動や雲粒子の特質が観測されたと言える。観測された諸性質を完全に説明するには今しばらくの考察が必要であるが、1年以内には投稿論文としてまとめられるであろうと考えている。
    上記二点の結果について、2月末に横浜で開催された「ブルーアース06みらいシンポジウム」にて発表し、他の研究者らと議論、情報交換を行った。
    また、過去の観測およびデータ解析の結果を、共同研究者らと投稿論文にまとめて発表した。
    日本学術振興会, 若手研究(B), 北海道大学, 16740264
  • 大気微量成分観測とモデリングによる熱帯対流圏界層内脱水過程の解明
    科学研究費助成事業
    2003年 - 2005年
    長谷部 文雄; 塩谷 雅人; 藤原 正智; 西 憲敬; 柴田 隆; 岩崎 俊樹
    熱帯対流圏界層(TTL)内脱水過程を解明し、熱帯下部成層圏(TLS)水蒸気の長期トレンドを鏡面冷却型水蒸気ゾンデ観測により検出するために、2003年12月、2004年12月-2005年1月、2005年12月-2006年1月にオゾン・水蒸気ゾンデ観測を実施した。観測期間中、TTL/TLS領域の水蒸気に顕著なトレンドは見出されていない。脱水過程の解明を目的に、大気塊の移流経路に沿ってTarawa、Biak、Bandung、Kototabang、Hanoiに観測点を配置する共に、Koror付近に係留中の「みらい」に乗船して観測の機会を得た。下部TTL内で観測された大気塊の保持する水蒸気量とその大気塊の過去数日間の温度履歴との間には、よい対応が確認された。より精密な評価を行うには、同一大気塊を複数回観測するmatch法が有効である。ゾンデ観測値のもつ誤差の評価、客観的なmatch判定基準の確立、移流大気塊への対流雲貫入の評価、客観解析場のもつバイアスの評価など多くの注意点を念頭に、現在、慎重に解析を進めている。こうした水蒸気観測と相補的な観測として、ライダーによる巻雲の観測も実施した。これにより、ゾンデ観測された水蒸気分布における巻雲存在高度の推定や巻雲粒子周囲の気象条件の特定が可能になる。解析の結果、巻雲の存在と過飽和度との間に興味深い対応が見出された。この例については、更に詳細に解析中である。一方、モデリングの観点からの研究においては、等温位面上における質量の重み付き帯状平均という新しい枠組みの構築とそれを利用したオゾン輸送の解釈、大気微量成分分布再現実験において同化される気象変数への依存性の研究などが進展した。これらの成果は継続課題に引き継がれ、研究の更なる発展が期待できる。
    日本学術振興会, 基盤研究(A), 北海道大学, 15204043
  • 赤道域の積雲対流と大気波動に関するゾンデ観測とデータ同化モデリングによる研究
    科学研究費助成事業
    2000年 - 2002年
    中村 卓司; 津田 敏隆; 堀之内 武; 西 憲敬; 竹見 哲也; 藤原 正智
    赤道域においては積雲対流が極めて活発であり、これにより励起される大気波動が上方伝搬して下層・中層大気の循環に大きな影響を与え、さらに熱圏へのエネルギー輸送においても大きな働きをなす。本研究では時間空間サンプリングの限られる「観測」だけでは明らかにできないこのような過程を解明するために、まずこれまでに蓄積された観測データを幅広く活用するとともに、新たな高精度観測をインドネシア域で行い、これらを用いてデータ同化手法をもちいた数値モデリングを行うことで得られる4次元データセットを観測と詳細に比較することで観測と数値モデルの有機的結合をはかり、積雲対流と大気波動の詳細なメカニズムを明らかにした。まず、高精度水蒸気ゾンデ観測をインドネシアにて行うことで、対流圏界面付近の微量な水蒸気量の変動を明らかにし、積雲対流に伴う赤道域の物質輸送を明らかにした。さらに、大気光イメージング観測をインドネシア域で1年以上にわたって行うことで、赤道域の中間圏界面付近の小スケール重力波の年周変化を世界で初めて明らかにし、積雲対流の水平分布が大きな影響を与えることを示した。さらに長期間のMLT領域レーダー観測の結果を解析して衛星データと比較することで、赤道域中間圏界面の季節内振動と下層起源の大気波動の関係を明らかにした。さらに観測データを取り込んだ3次元数値モデルを用いて、積雲対流が励起する大気重力波が中間圏界面領域まで伝搬して砕波する詳細を初めて明らかにし、大気光イメージャ観測の結果を詳細に比較検討することで、中間圏界面での重力波の励起・伝搬・砕波と大気不安定構造のメカニズムを明らかにした。今後、モデルの広域化・精密化をはかるとともに、新たな衛星観測なども取り込むことで大気波動の下層・中層大気内での全地球的なインパクトの研究に発展できるものと期待される。
    日本学術振興会, 基盤研究(B), 京都大学, 12440127
  • 熱帯地域における大気波動に伴う成層圏-対流圏大気交換過程
    科学研究費助成事業
    2000年 - 2002年
    藤原 正智
    1.京都大学とインドネシア航空宇宙庁によりインドネシア共和国スマトラ島コトタバンに設置された赤道大気レーダー(Equatorial Atmosphere Radar)のデータ解析を行い、対流圏界面領域の物質輸送に重要な役割を果たしているはずである乱流強度の変動の様子を世界で初めて明らかにし、さらにそれを引き起こしている大気擾乱の特定を行った。その結果は、論文リストに示すように2本の論文として発表した。
    2.ラジオゾンデ搭載用で安価で操作が容易でありながら、鏡面冷却方式という高精度な測定原理を持つ商用水蒸気センサーSnow Whiteについて、これまで2年間の熱帯地域における試験運用の結果を2本の論文にまとめ、Joumal of Atmospheric and Oceanic Technology誌に投稿した(2003年3月現在、2回目の査読中)。また、6月にはキリバス共和国クリスマス島、10月にはスリナム共和国、1月にはインドネシア共和国にてSnow Whiteやオゾンゾンデ等の同時集中観測を行い、成層圏対流圏大気交換過程に関する観測的研究を実施した。現在データ解析を行っている。
    3.東京大学気候システム研究センター・国立環境研究所所有の大気大循環モデルに使用されている放射コードと、熱帯での大気観測プロファイルデータとを用いて、放射加熱・冷却率プロファイルの算出を行い、熱帯上部対流圏〜対流圏界面領域の放射の観点からの特徴を明らかにした。現在2本の論文を共同で準備しており、1本目は、熱帯上部対流圏の気温微細構造が水蒸気の放射過程によって形成されており、さらにこのことが同領域の東風ジェットの成因となっていることを論じたものであり、2本目は英米の研究者とともに異なる放射コードを持ち寄り放射計算結果の相違を議論したものである。
    4.論文リストに示すように、前年度までに実施したいくつかの研究を、共同研究者とともにまとめて発表した。
    日本学術振興会, 特別研究員奨励費, 00J06668
  • 大気波動に伴う成層圏対流圏大気交換過程
    科学研究費助成事業
    1998年 - 1999年
    藤原 正智
    日本学術振興会, 特別研究員奨励費, 東京大学, 98J04543