Variations in the annual cycle of the East Asian monsoon and its phase-induced interseasonal rainfall anomalies in China  

东亚季风年循环和位相异常导致的降水年际变化特征

作　　者：JIANG Song ZHU Congwen JIANG Ning 

机构地区：[1]Institute of Climate System,Chinese Academy of Meteorological Sciences,Beijing,China

出　　处：《Atmospheric and Oceanic Science Letters》2020年第4期316-322,共7页大气和海洋科学快报（英文版）

基　　金：This work was jointly supported by the National Natural Science Foundation of China[grant numbers 41830969 and 41775052];the National Key R&D Program[grant number 2018YFC1505904];the Basic Scientific Research and Operation Foundation of CAMS[2018Z006 and 2018Y003];It was also supported by the Jiangsu Collaborative Innovation Center for Climate Change.

摘　　要：The East Asian monsoon(EAM)exhibits a robust annual cycle with significant interannual variability.Here,the authors find that the EAM annual cycle can be decomposed into the equinoctial and solstitial modes in the combined sea level pressure,850-hPa low-level wind,and rainfall fields.The solstitial mode shows a zonal pressure contrast between the continental thermal low and the western Pacific subtropical high,reaching its peak in July and dominating the East Asian summer monsoon.The equinoctial mode shows an approximate zonal contrast between the low-level cyclone over the east of the Tibetan Plateau and the western Pacific anticyclone over the east of the Philippines.It prevails during the spring rainy season in South China and reaches its peak in April.The interannual variations of the lead–lag phase of the two modes may result in the negative correlation of rainfall anomalies in North China between spring and fall and in South China between winter and summer,which provides a potential basis for the across-seasonal prediction of rainfall.The warm phase of ENSO in winter could give rise to the reverse interseasonal rainfall anomalies in South China,while the SST anomaly in the Northwest Pacific Ocean may regulate the rainfall anomaly in North China.基于1979-2016年资料分析,本文发现,东亚季风可以分解为春分和夏至两个模态,分别反映的是春夏和秋冬影响我国华南和大陆的环流降水特征。东亚夏季风的季节进程表现为春分模态向夏至模态的演变。在年际尺度上,春分和夏至模态的时间位相变化表现出显著的正相关,前冬的ENSO和西北太平洋海温变化可导致东亚季风年循环年际异常,进而造成华南和华北部分地区的冬夏和春秋降水隔季反向变化,这为我国跨季节的降水气候预测提供了理论依据。

关 键 词：Annual cycle East Asian monsoon interannual variability 

分 类 号：P425.42[天文地球—大气科学及气象学] P426.6