抄録
Observational features of atmospheric fields during a zonal wave number 2-type major sudden stratospheric warming (MSSW) event in February 2018 (MSSW18) are analyzed using the Japanese 55-year Reanalysis, satellite measurements by a microwave limb sounder, and a new three-dimensional wave activity flux. MSSW18 is characterized by a clear polar vortex split, continuance of easterlies with evident double peaks, clear planetary wave propagation in the easterly region of the upper stratosphere and extraordinary upward propagation of wave number 2 planetary waves from the upper troposphere. The upward propagation peak is comparable to that during an MSSW event in January 2009 (MSSW09), although MSSW18 shows relatively modest warming, unclear disappearance of the stratopause and weak stratopause elevation compared to those during MSSW09. Further analyses reveal that wave packets propagates upward simultaneously in both the Eastern and Western Hemispheres. Those observed in the Eastern Hemisphere converge strongly at the western edge of the Aleutian High, and most of them do not propagate further into the upper stratosphere. The wave packets observed in the Western Hemisphere propagate locally into the upper stratosphere over North America despite the fact that easterlies were predominant there in the mature stage of MSSW18. Furthermore, the results of our study reveal that the regions and levels of wave packet attenuation correspond well to the areas that smaller-scale waves have weak eastward phase tilt or are in the quasi-barotropic condition during MSSW18, whereas during MSSW09 the westward phase tilts of smaller-scale waves were clearly visible in the upper stratosphere.
| 元の言語 | 英語 |
|---|---|
| ページ（範囲） | 6120-6142 |
| ページ数 | 23 |
| ジャーナル | Journal of Geophysical Research: Atmospheres |
| 巻 | 124 |
| 発行部数 | 12 |
| DOI | |
| 出版物ステータス | 出版済み - 6 27 2019 |
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All Science Journal Classification (ASJC) codes
- Geophysics
- Forestry
- Oceanography
- Aquatic Science
- Ecology
- Water Science and Technology
- Soil Science
- Geochemistry and Petrology
- Earth-Surface Processes
- Atmospheric Science
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science
- Palaeontology
これを引用
Diagnostics of a WN2-Type Major Sudden Stratospheric Warming Event in February 2018 Using a New Three-Dimensional Wave Activity Flux. / Harada, Yayoi; Sato, Kaoru; Kinoshita, Takenari; Yasui, Ryosuke; Hirooka, Toshihiko; Naoe, Hiroaki.
：: Journal of Geophysical Research: Atmospheres, 巻 124, 番号 12, 27.06.2019, p. 6120-6142.研究成果: ジャーナルへの寄稿 › 記事
}
TY - JOUR
T1 - Diagnostics of a WN2-Type Major Sudden Stratospheric Warming Event in February 2018 Using a New Three-Dimensional Wave Activity Flux
AU - Harada, Yayoi
AU - Sato, Kaoru
AU - Kinoshita, Takenari
AU - Yasui, Ryosuke
AU - Hirooka, Toshihiko
AU - Naoe, Hiroaki
PY - 2019/6/27
Y1 - 2019/6/27
N2 - Observational features of atmospheric fields during a zonal wave number 2-type major sudden stratospheric warming (MSSW) event in February 2018 (MSSW18) are analyzed using the Japanese 55-year Reanalysis, satellite measurements by a microwave limb sounder, and a new three-dimensional wave activity flux. MSSW18 is characterized by a clear polar vortex split, continuance of easterlies with evident double peaks, clear planetary wave propagation in the easterly region of the upper stratosphere and extraordinary upward propagation of wave number 2 planetary waves from the upper troposphere. The upward propagation peak is comparable to that during an MSSW event in January 2009 (MSSW09), although MSSW18 shows relatively modest warming, unclear disappearance of the stratopause and weak stratopause elevation compared to those during MSSW09. Further analyses reveal that wave packets propagates upward simultaneously in both the Eastern and Western Hemispheres. Those observed in the Eastern Hemisphere converge strongly at the western edge of the Aleutian High, and most of them do not propagate further into the upper stratosphere. The wave packets observed in the Western Hemisphere propagate locally into the upper stratosphere over North America despite the fact that easterlies were predominant there in the mature stage of MSSW18. Furthermore, the results of our study reveal that the regions and levels of wave packet attenuation correspond well to the areas that smaller-scale waves have weak eastward phase tilt or are in the quasi-barotropic condition during MSSW18, whereas during MSSW09 the westward phase tilts of smaller-scale waves were clearly visible in the upper stratosphere.
AB - Observational features of atmospheric fields during a zonal wave number 2-type major sudden stratospheric warming (MSSW) event in February 2018 (MSSW18) are analyzed using the Japanese 55-year Reanalysis, satellite measurements by a microwave limb sounder, and a new three-dimensional wave activity flux. MSSW18 is characterized by a clear polar vortex split, continuance of easterlies with evident double peaks, clear planetary wave propagation in the easterly region of the upper stratosphere and extraordinary upward propagation of wave number 2 planetary waves from the upper troposphere. The upward propagation peak is comparable to that during an MSSW event in January 2009 (MSSW09), although MSSW18 shows relatively modest warming, unclear disappearance of the stratopause and weak stratopause elevation compared to those during MSSW09. Further analyses reveal that wave packets propagates upward simultaneously in both the Eastern and Western Hemispheres. Those observed in the Eastern Hemisphere converge strongly at the western edge of the Aleutian High, and most of them do not propagate further into the upper stratosphere. The wave packets observed in the Western Hemisphere propagate locally into the upper stratosphere over North America despite the fact that easterlies were predominant there in the mature stage of MSSW18. Furthermore, the results of our study reveal that the regions and levels of wave packet attenuation correspond well to the areas that smaller-scale waves have weak eastward phase tilt or are in the quasi-barotropic condition during MSSW18, whereas during MSSW09 the westward phase tilts of smaller-scale waves were clearly visible in the upper stratosphere.
UR - http://www.scopus.com/inward/record.url?scp=85067475993&partnerID=8YFLogxK
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U2 - 10.1029/2018JD030162
DO - 10.1029/2018JD030162
M3 - Article
VL - 124
SP - 6120
EP - 6142
JO - Journal of Geophysical Research
JF - Journal of Geophysical Research
SN - 0148-0227
IS - 12
ER -