Clarification of genesis and development mechanism of cumulonimbus with the next-generation data assimilation and ensemble simulations

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K17804
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Meteorology/Physical oceanography/Hydrology
• Research Institution: Japan, Meteorological Research Institute
• Principal Investigator: Yokota Sho 気象庁気象研究所, 気象観測研究部, 併任(第四研究室) (10723794)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 積乱雲 / データ同化 / アンサンブル予報 / 二重偏波レーダー / 赤外線カメラ

Outline of Final Research Achievements

Rainfalls generated from cumulonimbus were reproduced with the ensemble simulations by the data assimilation of dense observations (e.g., polarimetric radars), and it was shown that analyses based on the ensemble simulations can clarify the characteristics of atmospheric states that were suitable for the genesis of the rainfalls. Methods to improve rainfall forecasts were also suggested: radar data assimilation at points where rainfall forecasts are failed and assimilation of nonlinear physical values using iterative calculation of the nonlinear forecast model. Availability of atmospheric states in the lower layer observed by the infra-red camera was also examined.

Free Research Field

気象学

Academic Significance and Societal Importance of the Research Achievements

本研究で行ったアンサンブル予報に基づく降水の解析手法は、発生頻度が小さく複数の要因が考えられる複雑な気象現象を統計的に解析できる新しい手法として有用であり、学術的意義が大きい。また、本研究のアンサンブル予報に基づく解析で得られた降水の発生に適した大気場の特徴、本研究で提案した降水予測改善のための新しいデータ同化手法や赤外線カメラによる観測の利用などは、豪雨予測に向けた数値モデルやデータ同化手法の高度化に大きく寄与する。