长江流域雨季特征时空变化规律及遥相关分析

SPATIO-TEMPORAL PATTERNS OF RAINY-SEASON FEATURES AND ANALYSIS OF TELECONNETION IN THE YANGTZE RIVER BASIN

利用1960—2020年长江流域126个气象站点的降雨数据,采用滑动t检验法确定长江流域各站点的雨季起讫时间和雨季降雨量的时空分布规律,揭示了长江流域雨季特征变化与海表温度及大气环流的相关性。结果表明:长江流域的雨季开始时间、结束时间以及雨季降雨量具有明显的年代际和空间变化特征。从空间分布上看,雨季特征具有从东南向西北递减的带状分布规律;从时间变化规律上看,雨季特征具有明显的波动性。雨季特征的变化规律与海表温度及太平洋北部的反气旋密切相关,升高的海表温度会导致长江流域雨季开始时间延迟、结束时间提前以及降雨量减小,研究结果对掌握长江流域雨季特征与海表温度的遥相关性具有重要意义。

In this paper,rainfall data in 126 meteorological stations from 1960 to 2020 over the Yangtze River basin were chosen to explore spatial and temporal patterns of rainy-season features(i.e.,onset,retreat,and rainy-season precipitation).The multi-scale moving t-test was used to capture the onset and retreat of the rainy season in different stations.Furthermore,the teleconnections between seas surface temperature and rainy-season features were calculated to explore the underlying causes of the variability of rainy-season features.Results showed that onset,retreat,and rainy-season precipitation had prominent characteristics of inter-decadal and spatial changes.In terms of spatial patterns,onset,retreat,and rainy-season precipitation changed from southeast to northwest.The temporal regular of rainy-season features from 1960 to 2020 was explored.The Pettitt test was applied to detect the abruption point of rainy-season characteristics.It showed that the abruption points of rainy-season features were related to ENSO events.Furthermore,rainy-season features were related to ENSO and anti-cyclone in the northern Pacific Ocean.Warmer sea surface temperature would cause a later onset,earlier retreat,and less rainfall,which played a crucial role in water management in the Yangtze River basin.