Anomalies of Ocean and Atmospheric Circulation in 2013 and Their Impacts on Climate in China
Anomalies of oceanic and atmospheric circulations are analyzed and their impacts on temperature and precipitation anomalies of 2013 in China are discussed.The results show that the Arctic Oscillation (AO)experienced negative phase during the 2012/2013 winter.At 500 hPa,a“two troughs and one ridge”anomalous geopotential height pattern dominated the mid-high latitudes in Eurasia,leading to an enhanced ridge and trough over Urals and East Asia,respectively,and further leading to be colder than normal situ-ation over China.While the Siberian high exhibited strong intra-seasonal variations,the temperature over China had two-stage variations last winter,warmer in the early winter and colder in the late winter.Fur-ther research indicates that the reduced Arctic sea ice extent in the last autumn was responsible for the stronger East Asian winter monsoon.During the period from winter to summer 2013,the anomalous low sea surface temperature (SST)was observed in the tropical central and eastern Pacific,while abnormal high SST in tropical western Pacific and oceanic continent.As a response of atmospheric circulation to the anomalous tropical oceanic condition,the western Pacific subtropical high extended further north,leading to more precipitation over the northern part of China during the summer.Meanwhile,the northward ex-tending of the western Pacific subtropical high dominated most southern part of China,causing higher tem-perature and less precipitation than normal in the region in summer.In 2013,onset of South China Sea summer monsoon was 2 pentads earlier than normal and the ending was 4 pentads later than normal,and the intensity was weaker than normal.
国家科技期刊平台
NSTL
万方数据
维普
