Multiple Planetary Flow Regimes in the Southern Hemisphere
An observational study is made of low-frequency variations of the general circulation in the Southern Hemisphere troposphere with the aid of daily data analyzed at the National Meteorological Center (NMC). In the winter of 1983 there exist two typical patterns of the zonal mean geostrophic wind in t...
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Meteorological Society of Japan
1987
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ftkyotouniv:oai:repository.kulib.kyoto-u.ac.jp:2433/217794 2023-05-15T18:02:19+02:00 Multiple Planetary Flow Regimes in the Southern Hemisphere 南半球で解析された惑星規模の循環形態の多様性 Yoden, Shigeo Shiotani, Masato Hirota, Isamu 余田, 成男 塩谷, 雅人 廣田, 勇 1987-08 application/pdf http://hdl.handle.net/2433/217794 eng eng Meteorological Society of Japan 日本気象学会 10.2151/jmsj1965.65.4_571 https://www.jstage.jst.go.jp/article/jmsj1965/65/4/65_4_571/_article 0026-1165 http://hdl.handle.net/2433/217794 AA00702524 Journal of the Meteorological Society of Japan. Ser. II 65 4 571 586 気象集誌 第2輯 © 1987, Meteorological Society of Japan (MSJ) Permission has been provided by MSJ to place a copy of the papers on this server. MSJ will not guarantee that the copy provided here is an accurate one published in the Journal journal article 1987 ftkyotouniv 2022-10-27T23:19:21Z An observational study is made of low-frequency variations of the general circulation in the Southern Hemisphere troposphere with the aid of daily data analyzed at the National Meteorological Center (NMC). In the winter of 1983 there exist two typical patterns of the zonal mean geostrophic wind in the meridional plane. We name them the single jet regime and the double jet regime, each of which persisted with a characteristic duration of a month and appeared twice alternatively. In the single jet regime, the subtropical jet at the tropopause level is strong and the stationary wave of zonal wavenumber (WN=)3 has a larger amplitude than WN=2. On the other hand, in the double jet regime the subtropical jet is weak and the polar night jet extends down to the surface at about 55°S. Dominant stationary planetary waves are WN=1 and 2. These two regimes are also observed in the three years 1980-1982. In terms of the quasi-geostrophic Eliassen-Palm (E-P) flux diagnostics, the vertical component of the E-P flux, which is proportional to the horizontal eddy heat flux, is larger around the mid-latitude troposphere in the single jet regime than in the double jet regime. Consequently, the convergence of the E-P flux, which acts as a wave drag on the mean westerly wind, is larger around the mid- and high latitude tropopause level in the single jet regime than in the double jet regime. The larger wave drag tends to keep the weaker westerlies in the single jet regime. An empirical orthogonal function (EOF) analysis is made to define an index of the zonal mean wind of two dimension The first component of EOF, which represents over 40% of the total variance, corresponds to the variations between the two regimes. The amplitude of this component is used as a kind of 'zonal index'. Time variation of the zonal index is not considered an internal oscillation with an intrinsic frequency because the 'period', which is not an appropriate concept for the present phenomenon, is different in each year. The transition between the regimes is ... Article in Journal/Newspaper polar night Kyoto University Research Information Repository (KURENAI) |
institution |
Open Polar |
collection |
Kyoto University Research Information Repository (KURENAI) |
op_collection_id |
ftkyotouniv |
language |
English |
description |
An observational study is made of low-frequency variations of the general circulation in the Southern Hemisphere troposphere with the aid of daily data analyzed at the National Meteorological Center (NMC). In the winter of 1983 there exist two typical patterns of the zonal mean geostrophic wind in the meridional plane. We name them the single jet regime and the double jet regime, each of which persisted with a characteristic duration of a month and appeared twice alternatively. In the single jet regime, the subtropical jet at the tropopause level is strong and the stationary wave of zonal wavenumber (WN=)3 has a larger amplitude than WN=2. On the other hand, in the double jet regime the subtropical jet is weak and the polar night jet extends down to the surface at about 55°S. Dominant stationary planetary waves are WN=1 and 2. These two regimes are also observed in the three years 1980-1982. In terms of the quasi-geostrophic Eliassen-Palm (E-P) flux diagnostics, the vertical component of the E-P flux, which is proportional to the horizontal eddy heat flux, is larger around the mid-latitude troposphere in the single jet regime than in the double jet regime. Consequently, the convergence of the E-P flux, which acts as a wave drag on the mean westerly wind, is larger around the mid- and high latitude tropopause level in the single jet regime than in the double jet regime. The larger wave drag tends to keep the weaker westerlies in the single jet regime. An empirical orthogonal function (EOF) analysis is made to define an index of the zonal mean wind of two dimension The first component of EOF, which represents over 40% of the total variance, corresponds to the variations between the two regimes. The amplitude of this component is used as a kind of 'zonal index'. Time variation of the zonal index is not considered an internal oscillation with an intrinsic frequency because the 'period', which is not an appropriate concept for the present phenomenon, is different in each year. The transition between the regimes is ... |
author2 |
余田, 成男 塩谷, 雅人 廣田, 勇 |
format |
Article in Journal/Newspaper |
author |
Yoden, Shigeo Shiotani, Masato Hirota, Isamu |
spellingShingle |
Yoden, Shigeo Shiotani, Masato Hirota, Isamu Multiple Planetary Flow Regimes in the Southern Hemisphere |
author_facet |
Yoden, Shigeo Shiotani, Masato Hirota, Isamu |
author_sort |
Yoden, Shigeo |
title |
Multiple Planetary Flow Regimes in the Southern Hemisphere |
title_short |
Multiple Planetary Flow Regimes in the Southern Hemisphere |
title_full |
Multiple Planetary Flow Regimes in the Southern Hemisphere |
title_fullStr |
Multiple Planetary Flow Regimes in the Southern Hemisphere |
title_full_unstemmed |
Multiple Planetary Flow Regimes in the Southern Hemisphere |
title_sort |
multiple planetary flow regimes in the southern hemisphere |
publisher |
Meteorological Society of Japan |
publishDate |
1987 |
url |
http://hdl.handle.net/2433/217794 |
genre |
polar night |
genre_facet |
polar night |
op_relation |
10.2151/jmsj1965.65.4_571 https://www.jstage.jst.go.jp/article/jmsj1965/65/4/65_4_571/_article 0026-1165 http://hdl.handle.net/2433/217794 AA00702524 Journal of the Meteorological Society of Japan. Ser. II 65 4 571 586 気象集誌 第2輯 |
op_rights |
© 1987, Meteorological Society of Japan (MSJ) Permission has been provided by MSJ to place a copy of the papers on this server. MSJ will not guarantee that the copy provided here is an accurate one published in the Journal |
_version_ |
1766172126177394688 |