DOI: 10.1007/s00382-015-2570-9
Scopus记录号: 2-s2.0-84955643562
论文题名: Northern East Asian low and its impact on the interannual variation of East Asian summer rainfall
作者: Lin Z. ; Wang B.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2016
卷: 46, 期: 2017-01-02 起始页码: 83
结束页码: 97
语种: 英语
英文关键词: Cut-off lows
; East Asian summer monsoon
; Northern East Asian low
; Polar Eurasian teleconnection
; Subtropical front
; Western North Pacific subtropical high
英文摘要: The strength of the East Asian summer monsoon and associated rainfall has been linked to the western North Pacific subtropical high (WNPSH) and the lower-tropospheric low pressure system over continental East Asia (EA). In contrast to the large number of studies devoted to the WNPSH, little is known about the variability of the East Asian continental low. The present study delineates the East Asian continental low using 850-hPa geopotential height. Since the low is centered over northern EA (NEA), we refer to it as the NEA low (NEAL). We show that the intensity of the NEAL has large interannual variation, with a dominant period of 2–4 years. An enhanced NEAL exhibits a barotropic structure throughout the whole troposphere, which accelerates the summer-mean upper-tropospheric westerly jet and lower-tropospheric monsoon westerly to its south. We carefully identify the anomalous NEAL-induced rainfall anomalies by removal of the tropical heating effects. An enhanced NEAL not only increases rainfall locally in northern Northeast China, but also shifts the East Asian subtropical front northward, causing above-normal rainfall extending eastward from the Huai River valley across central-northern Japan and below-normal rainfall in South China. The northward shift of the East Asian subtropical front is attributed to the following processes without change in the WNPSH: an enhanced NEAL increases meridional pressure gradients and the monsoon westerly along the East Asian subtropical front, which in turn induces a cyclonic shear vorticity anomaly to its northern side. The associated Ekman pumping induces moisture flux convergence that shifts the East Asian subtropical front northward. In addition, the frequent occurrence of synoptic cut-off lows is found to be associated with an enhanced NEAL. Wave activity analysis indicates that the interannual intensity change of the NEAL is significantly associated with the extratropical Polar Eurasian teleconnection, in addition to the forcing of the tropical WNP heating. © 2015, Springer-Verlag Berlin Heidelberg. 资助项目: MEST, National Natural Science Foundation of China
; NRF, National Natural Science Foundation of China
; NSFC, National Natural Science Foundation of China
; NSFC, National Natural Science Foundation of China
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/53868
Appears in Collections: 过去全球变化的重建
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作者单位: State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China; International Pacific Research Center, and Department of Meteorology, University of Hawai‘i at Mānoa, Honolulu, HI, United States; Earth System Modelling Center, Nanjing University of Information Science and Technology, Nanjing, China
Recommended Citation:
Lin Z.,Wang B.. Northern East Asian low and its impact on the interannual variation of East Asian summer rainfall[J]. Climate Dynamics,2016-01-01,46(2017-01-02)