15:45 〜 16:00
[AAS10-08] 2021年1月に発生した北半球大規模突然昇温における惑星規模波束伝播の特徴（第2報）
キーワード：成層圏突然昇温、惑星規模波束伝播、3次元波活動度フラックス
Observational features of atmospheric fields during a major sudden stratospheric warming (MSSW) event occurring in January 2021 (MSSW21) are investigated by the use of the Japanese 55-year Reanalysis (JRA-55) on the basis of the three-dimensional wave activity flux (3D-flux-W, Kinoshita and Sato 2013; Sato et al. 2013; Harada et al. 2019). MSSW21 is characterized by strong easterlies over 70 m s-1 around the stratopause in early January 2021, a mixed signature of wavenumber 1 (WN1), WN2 and WN3 planetary waves, and repetition of polar vortex splitting. In relation to that, wave packets repeatedly propagated upward in the Eastern Hemisphere during MSSW21: In the early stage, localized wave packets propagated upward into the upper stratosphere over western Siberia. On the other hand, in the mature stage (mid-January 2021), upward wave-packet propagation was observed over eastern Siberia even in the easterly region of the upper stratosphere.
In this report, we add Japanese Reanalysis for Three Quarters of a Century (JRA-3Q) as a dataset for analysis, which is being conducted by the Japan Meteorological Agency (JMA). In JRA-3Q data assimilation system, vertical levels are increased up to 100 layers (the top level of is 0.01 hPa) which covers the whole stratosphere and the lower mesosphere, and includes non-orographic gravity wave drag based on Scinocca (2003). As an early result, we found that the consistency of momentum budget in JRA-3Q is improved compared with that of JRA-55 not only in the upper stratosphere but also in the lower mesosphere. We are going to show further results on MSSW21 using 3D-flux-W.
In this report, we add Japanese Reanalysis for Three Quarters of a Century (JRA-3Q) as a dataset for analysis, which is being conducted by the Japan Meteorological Agency (JMA). In JRA-3Q data assimilation system, vertical levels are increased up to 100 layers (the top level of is 0.01 hPa) which covers the whole stratosphere and the lower mesosphere, and includes non-orographic gravity wave drag based on Scinocca (2003). As an early result, we found that the consistency of momentum budget in JRA-3Q is improved compared with that of JRA-55 not only in the upper stratosphere but also in the lower mesosphere. We are going to show further results on MSSW21 using 3D-flux-W.