Advances in Earth Science ›› 2012, Vol. 27 ›› Issue (3): 304-320. doi: 10.11867/j.issn.1001-8166.2012.03.0304
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Wang Wanli 1,2,Wang Haoyue 3,Xie Yingqi 3,Wang Weiguo 3,Wang Zuwu 2,Wang Kai 1,Du Liangmin 1,Deng Nansheng 2,Cai Shuming 2,Liu Yaolin 2
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Wang Wanli,Wang Haoyue,Xie Yingqi,Wang Weiguo,Wang Zuwu,Wan Wang Kai. Analysis of Decade Variation of East Asia Trough and West Pacific Subtropical High in Summer[J]. Advances in Earth Science, 2012, 27(3): 304-320.
The 500 hPa potential height field over East Asia has been investigated. Then outcome shows that averaged 500hPa height increased obviously in the past 40 years in this continent. The increase mainly takes place from April to October and mainly over Eurasia continent of west region less than 120°E. West ridge point of Subtropical High over west-north Pacific shifts obviously westward in this period, East Asia Trough displaces at least westward by 20 longitude contemporarily. Therefore, the total precipitation over North China possibly decreases, whereas that of Northwest China possibly increases in the wake of variation happening. In addition, the 500 hPa potential height field over Indian peninsula and Bay of Bangladeshalso increase simultaneously also. It is diagnosed through the formulas that those possible chief causes of westward displacement for East Asia Trough as well as for northward expansion of Subtropical High are continent-scale longitudinal Temperature Gradient decreases and the reduction in Equator-Pole Temperature Gradient at hemisphere-scale, respectively.