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Papers 【 display / non-display 】

• Two-Dimensional Idealized Hadley Circulation Simulation for Global High Resolution Model Development

  Ryuji Yoshida, Takanobu Yamaguchi, Graham Feingold

  Journal of Advaces in Modeling Earth Systems   14 ( 1 )   2022  [Reviewed]

  DOI

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  Language：English   Publishing type：Research paper (scientific journal)   Joint Work  

• Contributions of the Large-Scale Environment to the Typhoon Genesis of Faxai (2019)

  FUDEYASU Hironori, SHIMADA Udai, OIKAWA Yoshinori, EITO Hisaki, WADA Akiyoshi, YOSHIDA Ryuji, HORIN … Show more authors

  Journal of the Meteorological Society of Japan. Ser. II   advpub ( 0 )   617 - 630   2022  [Reviewed]

  DOI Web of Science CiNii Research

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  Language：English   Publishing type：Research paper (scientific journal)   Publisher：Meteorological Society of Japan   Joint Work  

  <p>This study investigated the atmospheric and oceanic contributions to the genesis of Typhoon Faxai in 2019. Our statistical analysis using the tropical cyclone genesis score (TGS) attributed the tropical disturbance that developed into Faxai (Pre-Faxai) to easterly waves (EWs). The EW score evaluated by a grid version of the TGS (Grid-EW) averaged around the occurrence of Pre-Faxai was approximately twice as large as the climatological mean, and it was the second largest value in the past 38 years. The Pre-Faxai area with high Grid-EW scores could be traced back to the eastern North Pacific (ENP) around August 25, 2019. The lower-troposphere environment characterized by high Grid-EW scores was favorable for vortex formation because it provided a containment area for moisture entrained by the developing circulation or lofted by the deep convection therein. The Pre-Faxai area with high Grid-EW scores moved westward due to the background easterly flow over the ENP and then entered the western North Pacific (WNP). The Typhoon Intensity Forecast Scheme (TIFS) showed that the important environments for its genesis were ocean conditions and the vertical wind shear. The oceanic conditions contributed to the development of Pre-Faxai as it traveled over the WNP. The enhancement of vertical wind shear and subsequent suppression of the development of Pre-Faxai were caused by the lower-troposphere easterly winds associated with high EW scores. They were also caused by upper-troposphere westerly winds associated with an upper cold low northwest of Pre-Faxai. When the vertical shear decreased with weakening of the upper cold low, Pre-Faxai reached tropical storm intensity on September 4. Therefore, TGS and TIFS detected Pre-Faxai 10 days before the typhoon arose, which indicates that monitoring environmental factors such as EW and vertical wind shear are important for disaster prevention.</p>

• How Significant are Low-Level Flow Patterns in Tropical Cyclone Genesis over the Western North Pacific?

  Yoshida Ryuji, Fudeyasu Hironori

  MONTHLY WEATHER REVIEW   148 ( 2 )   559 - 576   2020.2  [Reviewed]

  DOI Web of Science

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  Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Joint Work  

• Development Conditions for Tropical Storms over the Western North Pacific Stratified by Large-Scale Flow Patterns

  Fudeyasu Hironori, Yoshida Ryuji, Yamaguchi Munehiko, Eito Hisaki, Muroi Chiashi, Nishimura Shuji, … Show more authors

  Journal of the Meteorological Society of Japan. Ser. II   98 ( 1 )   61 - 72   2020

  DOI Web of Science CiNii Research

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  Language：English   Publishing type：Research paper (scientific journal)   Publisher：Meteorological Society of Japan   Joint Work  

  <p>This study investigated the characteristics and environmental conditions of tropical cyclones (TCs) over the western North Pacific from 2009 to 2017 that dissipated before reaching tropical storm strength (TDs) under unfavorable environmental conditions; we compared TDs with TCs that reached tropical storm strength (TSs) in terms of modulations of relevant large-scale flow patterns. The flow patterns were categorized based on five factors: shear line, confluence region, monsoon gyre, easterly waves, and Rossby wave energy dispersion from a preexisting cyclone. Among 476 cases, 263 TDs were detected using best-track data and early stage Dvorak analysis. The TCs in the environments associated with the confluence region or Rossby wave energy dispersion (easterly waves) tended to reach tropical storm strength (remain weak) compared with the other factors. The average locations of TDs at the time of cyclogenesis in the confluence region, monsoon gyre, and easterly waves (Rossby wave energy dispersion) in the summer and autumn were farther to the west (east and north) than those of TSs that exhibited the same factors. The environments around TDs were less favorable for development than those around TSs, as there were significant differences in atmospheric (oceanic) environmental parameters between TDs and TSs in the factors of confluence region, easterly waves, and Rossby wave energy dispersion (shear line, monsoon gyre, and Rossby wave energy dispersion). The environmental conditions for reaching tropical storm strength over their developing stage, using five factors, can be summarized as follows: higher tropical cyclone heat potential in the shear line and monsoon gyre, weak vertical shear in the confluence region, wet conditions in the easterly waves, and higher sea surface temperatures and an intense preexisting cyclone in Rossby wave energy dispersion from a preexisting cyclone.</p>

• Environmental Factors Contributing to Tropical Cyclone Genesis over the Western North Pacific.

  Yoshida Ryuji, Hirohiko Ishikawa

  MONTHLY WEATHER REVIEW   141   451 - 467   2013  [Reviewed]

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  Language：English   Publishing type：Research paper (scientific journal)   Joint Work  

Review Papers 【 display / non-display 】

Review Papers 【 display / non-display 】

• Changes in extended boreal summer tropical cyclogenesis associated with large-scale flow patterns over the western North Pacific in response to the global warming hiatus

  Kai Zhao and Haikun Zhao and Graciela B. Raga and Ryuji Yoshida and Weiqiang Wang and Philip J. Klo … Show more authors

  Climate Dynamics   56 ( 1-2 )   515 - 535   2021.1

  DOI

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  Language：The in addition, foreign language   Publishing type：Article, review, commentary, editorial, etc. (bulletin of university, research institution)   Publisher：Springer Science and Business Media {LLC}   Single Work  

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Other external funds procured 【 display / non-display 】

• 室内実験によるMicrophysicsスキームの精緻化

  Grant number：JPMJMS2282-04  2022.6 - 2023.3

  Japan Science and Technology Agency  JST委託研究「ムーンショット型研究開発事業

  Investigator(s)：筆保弘徳（横浜国立大学）

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  Authorship：Principal investigator 

  雲の生成・消滅をつかさどる雲微物理過程（Microphysics）は、台風の数値シミュレーションにおいて重要な役割を担う。本研究課題は、室内実験の実権データをベースに現存のMicrophysicsスキームの精緻化・改良によって、数値モデルの湿潤過程の表現性を改善させ、台風の理解・予測・制御に関連する数値シミュレーションの高度化を目指すものである。

Presentations 【 display / non-display 】

Presentations 【 display / non-display 】

• 高解像度数値モデルの開発プラットフォームとしての理想化ハドレー循環シミュレーション

  吉田龍二 (横浜国立大学), Takanobu Yamaguchi (NOAA/CIRES UCB), Graham Feingold (NOAA)

  日本気象学会2022年秋季大会  2022.10 

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  Event date： 2022.10

  Language：Japanese   Presentation type：Oral presentation (general)  

  Venue：北海道大学  

Charge of on-campus class subject 【 display / non-display 】

Charge of on-campus class subject 【 display / non-display 】

• 2023   大気科学Ⅱ

  College of Urban Sciences

• 2023   大気科学Ⅰ

  College of Urban Sciences

• 2023   気候変動概論Ⅱ

  College of Urban Sciences

• 2023   気候変動概論Ⅰ

  College of Urban Sciences

• 2023   Exercises in Earth Science

  College of Urban Sciences

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