Interdecadal variability of summer precipitation in the Three River Source Region: Influences of SST and zonal shifts of the East Asian subtropical westerly jet  

作　　者：Yumeng Liu Xianhong Meng Lin Zhao S-Y.Simon Wang Lixia Zhang Zhaoguo Li Chan Wang Yingying An 

机构地区：[1]Key Laboratory of Cryospheric Science and Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou,China [2]Zoige Plateau Wetlands Ecosystem Research Station,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou,China [3]University of Chinese Academy of Sciences,Beijing,China [4]Utah Climate Center,Utah State University,Logan,USA [5]The State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing,China

出　　处：《Atmospheric and Oceanic Science Letters》2024年第5期47-53,共7页大气和海洋科学快报（英文版）

基　　金：supported by the 2nd Scientific Expedition to the Qinghai–Tibet Plateau[grant number 2019QZKK0102];the National Natural Science Foundation of China[grant number 42275045,41975012];the West Light Foundation of the Chinese Academy of Sciences[grant number xbzg-zdsys-202215];the Science and Technology Research Plan of Gansu Province[grant number 20JR10RA070];the Youth Innovation Promotion Association of the Chinese Academy of Sciences[grant number QCH2019004];iLEAPs(integrated Land Ecosystem–Atmosphere Processes Study).

摘　　要：Summer precipitation in the Three Rivers Source Region(TRSR)of China is vital for the headwaters of the Yellow,Yangtze,and Lancang rivers and exhibits significant interdecadal variability.This study investigates the influence of the East Asian westerly jet(EAWJ)on TRSR rainfall.A strong correlation is found between TRSR summer precipitation and the Jet Zonal Position Index(JZPI)of the EAWJ from 1961 to 2019(R=0.619,p<0.01).During periods when a positive JZPI indicates a westward shift in the EAWJ,enhanced water vapor anomalies,warmer air,and low-level convergence anomalies contribute to increased TRSR summer precipitation.Using empirical orthogonal function and regression analyses,this research identifies the influence of large-scale circulation anomalies associated with the Atlantic–Eurasian teleconnection(AEA)from the North Atlantic(NA).The interdecadal variability between the NA and central tropical Pacific(CTP)significantly affects TRSR precipitation.This influence is mediated through the AEA via a Rossby wave train extending eastward along the EAWJ,and another south of 45°N.Moreover,the NA–CTP Opposite Phase Index(OPI),which quantifies the difference between the summer mean sea surface temperatures of the NA and the CTP,is identified as a critical factor in modulating the strength of this teleconnection and influencing the zonal position of the EAWJ.本研究探讨了年代际东亚西风急流的纬向移动对黄河,长江和澜沧江源头一3三江源区夏季降水的影响.研究发现,在1961--2019年间,三江源区夏季降水量与急流纬向位置指数(JZPD)在年代际尺度上存在强正相关(R=0.619,p<0.01).当JZPI呈正值,也就是东亚西风急流向西移动时,增强的水汽,温暖的气流和低层辐合异常有助于三江源区夏季降水增加.北大西洋与中太平洋之间的年代际变化对三江源区的降水有着显著的影响,主要以北大西洋欧亚遥相关(AEA)方式,通过沿东亚西风急流向东延伸的罗斯贝波列,以及45°N以南的另-波列来影响三江源区的降水进一步分析发现,北大西洋与中太平洋反向相位指数(OPI)作为一个关键因素,可量化北大西洋与中太平洋之间夏季平均海表温度的差异,调控该遥相关的强度并影响急流的纬向位置.

关 键 词：Summer precipitation East Asian subtropical westerly jet Three River Source Region Atlantic-Eurasian teleconnection 

分 类 号：P426.6[天文地球—大气科学及气象学]