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タイトル: | Wave-4 pattern of the equatorial mass density anomaly: A thermospheric signature of tropical deep convection |
著者: | Liu, Huixin Yamamoto, Mamoru https://orcid.org/0000-0002-4957-764X (unconfirmed) Lühr, Hermann |
発行日: | Sep-2009 |
出版者: | American Geophysical Union (AGU) |
誌名: | Geophysical Research Letters |
巻: | 36 |
号: | 18 |
論文番号: | L18104 |
抄録: | The equatorial mass density anomaly (EMA) is an anomalous latitudinal distribution of the atmospheric mass density, with its equinox configuration consisting of a density trough near the Earth's dip equator flanked by density crests around ±25° dip latitude. As a novel feature, this study reveals a pronounced 4-peak longitudinal pattern of the EMA, which is in reminiscence of the wave-4 like structure in the neutral wind and the equatorial ionization anomaly (EIA). It is found that the wave-4 modulation in the EMA trough region is in phase with that in the EMA crest region, in contrast to the 180° phase reversal for the case of EIA. This difference strongly suggest that although the latitudinal structure of the EMA is principally caused by the EIA via ion drag, its wave-4 pattern likely arises from different sources. The direct penetration of the non-migrating diurnal tides DE3 to the F-region height or thermal budget modulation by the composition NO at lower thermosphere are discussed as plausible candidates. Our results reveal a 4-hour phase lag between the wave-4 patterns in neutral density and wind, and a 2% peak-to-peak amplitude of the neutral density wave-4 pattern. These results find good agreements with theoretical predictions based on direct penetration of the DE3 to F-regions heights, hence strongly support this mechanism. Our observations thus add further evidences for the influence of tropical deep convection on the thermospheric dynamics. |
著作権等: | Copyright 2009 by the American Geophysical Union. この論文は出版社版でありません。引用の際には出版社版をご確認ご利用ください。 This is not the published version. Please cite only the published version. |
URI: | http://hdl.handle.net/2433/95082 |
DOI(出版社版): | 10.1029/2009GL039865 |
出現コレクション: | 学術雑誌掲載論文等 |
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