Using Observations near the Poles in the AFES-LETKF Data Assimilation System
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- Yamazaki Akira
- Application Laboratory, JAMSTEC
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- Enomoto Takeshi
- Application Laboratory, JAMSTEC Disaster Prevention Research Institute, Kyoto University
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- Miyoshi Takemasa
- Application Laboratory, JAMSTEC RIKEN Advanced Institute for Computational Science Department of Atmospheric and Oceanic Science, University of Maryland
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- Kuwano-Yoshida Akira
- Application Laboratory, JAMSTEC
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- Komori Nobumasa
- Application Laboratory, JAMSTEC
説明
<p>The observation operators in the local ensemble transform Kalman filter (LETKF) were improved to enable use of observations in the vicinity of the poles in the data assimilation system composed of the atmospheric general circulation model for the Earth Simulator (AFES) and the LETKF. The improved observation operators allow to assimilate the observations located south (north) of southernmost (northernmost) Gaussian grid latitudes. An algorithm for searching the nearest observations from an analyzed grid for error covariance localization was also modified to efficiently assimilate observations near the poles.</p><p>The new algorithms were incorporated into the LETKF, and the impacts of routine radiosonde observations at the South Pole during the periods of July 2012 and January 2013 were assessed. The radiosonde observations suppressed an artificial expansion of the analysis ensemble spread which occasionally caused numerical instability in the upper troposphere and the lower stratosphere over the Antarctic regions. The analysis was also improved in the Antarctic regions.</p>
収録刊行物
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- SOLA
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SOLA 13 (0), 41-46, 2017
公益社団法人 日本気象学会
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詳細情報 詳細情報について
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- CRID
- 1390001205222886400
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- NII論文ID
- 130006895313
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- ISSN
- 13496476
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- 本文言語コード
- en
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- データソース種別
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- JaLC
- Crossref
- CiNii Articles
- KAKEN
- OpenAIRE
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- 抄録ライセンスフラグ
- 使用不可