DOI: 10.1175/JCLI-D-11-00343.1
Scopus记录号: 2-s2.0-84862746441
论文题名: Upper-tropospheric forcing on late July monsoon transition in East Asia and the western North Pacific
作者: Wu C.-H. ; Chou M.-D.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2012
卷: 25, 期: 11 起始页码: 3929
结束页码: 3941
语种: 英语
Scopus关键词: Asian monsoon
; Downstream region
; East Asia
; East asian jet streams
; Geopotential height
; High potential
; Large-scale circulation
; Monsoon onset
; Monsoons
; North Pacific
; Rapid transitions
; Road patterns
; Summer monsoon
; Upper troposphere
; Western North Pacific
; Troposphere
; Atmospheric thermodynamics
; atmospheric circulation
; atmospheric convection
; atmospheric forcing
; geopotential
; jet stream
; monsoon
; summer
; troposphere
; upper atmosphere
; vorticity
; westerly
; Japan
; Pacific Ocean
; Pacific Ocean (North)
英文摘要: By investigating the large-scale circulation in the upper troposphere, it is demonstrated that the rapid late July summer monsoon transition in the East Asia and western North Pacific (EA-WNP) is associated with a weakened westerly at the exit of the East Asian jet stream (EAJS). Even in a normally stable atmosphere under the influence of the North Pacific (NP) high in late July, convection rapidly develops over the midoceanic region of the western NP (158°-25°N, 150°-170°E). Prior to the rapid transition, the EAJS weakens and shifts northward, which induces a series of changes in downstream regions; the northeastern stretch of the Asian high weakens, upper-tropospheric divergence in the region southwest of the mid-NP trough increases, and convection is enhanced. At the monsoon transition, upper-level high potential vorticity intrudes southward and westward, convection expand from the mid NP westward to cover the entire subtropical western NP, the lower-tropospheric monsoon trough deepens, surface southwesterly flow strengthens, and the western stretch of the NP high shifts northward ~10° latitude to the south of Japan. This series of changes indicates that the EA-WNP late July monsoon transition is initiated from changes in the upper-tropospheric circulation via the weakening of the EAJS south of ~45°N. The weakening of the EAJS south of ~45°N is related to a reduced gradient of the geopotential height on the northern flank of the Asian high, which is related to the massive inland heating and weakening of the South Asian monsoon circulation. The exact timing of the monsoon onset might be tied to the hypothesized "Silk Road pattern" and/or a strong weakening of the South Asian monsoon circulation. © 2012 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/52388
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Atmospheric Sciences, National Central University, Chung-Li, Taiwan
Recommended Citation:
Wu C.-H.,Chou M.-D.. Upper-tropospheric forcing on late July monsoon transition in East Asia and the western North Pacific[J]. Journal of Climate,2012-01-01,25(11)