Title: Inter-annual and Inter-decadal Variations of South Asian High in Summer and Its Influences on Flood/Drought Over Western Southwest China
Abstract: Based on the NCEP/NCAR re-analysis monthly data,the circulation characteristic index values given by the National Climate Center and daily precipitation data of 20 stations in the east of Southwest China from 1959 to 2006,the inter-annual and inter-decadal variations of South Asian High(SAH) in summer and its influences on drought/flood over eastern southwest China are analyzed.The results show that SAH is characterized by obvious inter-annual and inter-decadal variations.Two balancing modes exist for SAH,namely,the Tibetan High and the Iranian High,the former having a higher frequency than the latter.There is an accordant change tendency between the area of SAH and its main center intensity or its eastward model.The main center leans eastward-northward or westward-southward accordingly.A positive relationship exists between the average ridge position of SAH and its main center's latitude.SAH in summer is closely associated with WPSH(West Pacific Subtropical High) and the two show similar changes in the positions of their average ridges.When the ridge of SAH in summer moves northward(southward),it is(not) propitious to the appearance of circulation that brings less(more) summer rainfall in eastern Southwest China.Accordingly,the vapor transport and convergent anabatic velocity strengthens(weakens),and cold air active(fallow) comes from north.Consequently,this region is liable to drought or flood due to less or more precipitation.
Publication Year: 2012
Publication Date: 2012-01-01
Language: en
Type: article
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Cited By Count: 6
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