2020 Fiscal Year Final Research Report

A study on improvement of the Arctic atmospheric prediction

Research Project

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Project/Area Number	19K23454
Research Category	Grant-in-Aid for Research Activity Start-up
Allocation Type	Multi-year Fund
Review Section	0204:Astronomy, earth and planetary science, and related fields
Research Institution	University of Tsukuba
Principal Investigator	Akio Yamakami 筑波大学, 計算科学研究センター, 研究員 (30850135)
Project Period (FY)	2019-08-30 – 2021-03-31
Keywords	北極大気 / 気象予測 / アンサンブル予報 / 中期予報 / 延長予報
Outline of Final Research Achievements	Arctic forecast busts are investigated using operational forecasts. The occurrence frequency of forecast busts decreased from 2008 to 2012, and was between 2% and 6% for the period 2012-2019. Arctic forecast busts were most frequent in the May and July-September periods, but less frequent between December and March. The summertime forecast bust occurred more frequently when the initial pattern was the Greenland Blocking or Arctic Cyclone pattern rather than one of the other patterns. Also, the sub-seasonal predictability of the weekly mean geopotential height anomaly at 500 hPa were assessed. The skill over the North Pacific, Canada, and Greenland is higher than over other areas for week-3 and -4 forecasts. These peaks correspond to the centers of action for the teleconnection patterns in the Northern Hemisphere. Results suggest that the improvement in the mid-latitude upper-level jet rather than in the response to ENSO forcing in the tropics could lead to better S2S predictions.
Free Research Field	大気科学
Academic Significance and Societal Importance of the Research Achievements	北極海氷減少に伴う北極域の環境の変化は科学的に注目されている。また、北極海航路の活用などの観点から社会的にも注目されており、北極域における正確な気象予測の重要性が増している。予測精度急低下の研究結果は、人間活動が活発となる夏季に急低下が起こりやすいことを示すと同時に、日々の天気予報の予測の精度が下がりやすいパターンを示した。これは予報利用者にパターンによる予測の信頼度の違いについて注意喚起を行う有益な情報となり得る。また、延長予報は意思決定に利用されると考えられる。本研究の結果は、延長予報を有効に利用するためにはさらに精度を向上させる必要があり、それには偏西風の改善が必要であることを示唆した。