三江源地区冬季降水年代际变化特征及相关物理机制  

Interdecadal Variations of Winter Precipitation over the Three River Source Region in China and Associated Physical Mechanisms

作　　者：王腾 孙博[2] 王会军[2] 多典洛珠 卓永 WANG Teng;SUN Bo;WANG Huijun;DUODIAN Luozhu;ZHUO Yong(Qamdo Meteorological Service,Meteorology Bureau of Xizang Autonomous Region,Qamdo 854000;Key Laboratory of Meteorological Disaster,Ministry of Education(KLME)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD),Nanjing University of Information Science and Technology,Nanjing 210044;Meteorological Observatory of Xizang Autonomous Region,Lhasa 850000)

机构地区：[1]西藏昌都市气象局,昌都854000 [2]南京信息工程大学气象灾害教育部重点实验室/气象灾害预报预警与评估协同创新中心,南京210044 [3]西藏自治区气象台,拉萨850001

出　　处：《大气科学》2023年第6期1863-1875,共13页Chinese Journal of Atmospheric Sciences

基　　金：资助项目国家自然科学基金资助项目42088101;西藏自治区自然科学基金资助项目XZ202001ZR0014G、XZ202101ZR0041G。

摘　　要：本文主要利用1961/1962~2017/2018年CN05.1资料和NCEP/NCAR再分析资料,研究三江源地区(以下简称三江源)冬季降水的年代际变化特征及相关物理机制。结果表明:三江源冬季降水在20世纪80年代末期经历了一次由少到多的年代际增多。三江源冬季降水的年代际变化受乌拉尔山上空异常低压和贝加尔湖—中国东北部上空异常高压影响,与中高纬北大西洋海气相互作用有关。从20世纪80年代末期开始,中高纬北大西洋海温增暖可以导致海表面上空上升运动异常,对流活动增强,激发向东传播的大气环流波列,引起乌拉尔山上空的异常低压和贝加尔湖—中国东北部上空的异常高压。在异常低压与异常高压的影响下,极锋急流南移加强,引起三江源高空辐散,对流活动增强,导致三江源冬季降水增多;另一方面,贝加尔湖—中国东北部上空异常高压还可以通过引起三江源上空异常东风,引起三江源水汽通量辐合异常,导致冬季降水增多。此外,印度洋海温异常可能通过影响南支槽强度变化,进一步调制三江源冬季降水。This study investigates the interdecadal variability of winter precipitation and associated physical mechanisms caused over the Three-River Source(TRS)region based on gridded CN05.1 and NCEP/NCAR reanalysis datasets for the period of 1961/1962–2017/2018.The results show that the winter precipitation over the TRS region experienced intensification in the late 1980s.The anomalous low over the Ural Mountains and the anomalous high stretching from Lake Baikal to Northeast China,which can be connected with the ocean–atmosphere interaction over the North Atlantic,alter the decadal changes.Specifically,after the late 1980s,warm sea surface temperature(SST)anomalies over the midhigh latitudes of the North Atlantic may have contributed to abnormal ascending motions,strengthening convection and triggering the eastward wave train,resulting in the anomalous low over the Ural Mountains and the anomalous high extending from Lake Baikal to Northeast China.On the one hand,the coincidence of anomalous low and high intensified and shifted the polar front jet southward,triggering upper-level divergence and development of convection over the TRS region.On the other hand,the anomalous easterly wind over the TRS,generated by anomalous high extending from Lake Baikal to Northeast China,influenced the decadal intensification of winter precipitation over the TRS by generating an abnormal convergence of water vapor flux.Furthermore,positive SST anomalies in the Indian Ocean can also have an influence on the interdecadal variations in winter precipitation over the TRS region by influencing the south branch trough.

关 键 词：三江源 冬季降水 年代际变化 大气遥相关 海温异常 

分 类 号：P461[天文地球—大气科学及气象学]