宁夏地区雨季特征时空变化规律及其归因分析

Spatio-temporal evolution of rainy season characteristics and their causes in Ningxia Region

为揭示宁夏地区雨季特征时空变化规律及物理归因,利用1960~2020年宁夏地区9个气象站点的降水资料,基于滑动t检验法确定宁夏地区各个站点多个雨季特征(包括雨季开始时间、结束时间、持续时间、降雨量、降雨强度和降雨日数)的时空分布规律,分析大气环流、季风以及海表温度对宁夏地区雨季特征的影响。结果表明:宁夏地区的雨季开始时间和结束时间具有明显的年代际和空间变化特征,西北太平洋增强(减弱)的反气旋是宁夏地区雨季开始(结束)的重要信号。雨季降雨量和降雨强度在突变年份发生后,具有增强的趋势。多个雨季特征表现出与厄尔尼诺(ENSO)区域明显的负相关性,即升高的海表温度会导致宁夏地区雨季起讫时间的提前、降雨量和降雨强度以及雨季降雨日数的减小。研究成果可为探究宁夏地区雨季特征与海表温度的遥相关性提供参考。

To explore spatio-temporal evolution of rainy season characteristics and their underlying causes in Ningxia Region,rainfall data in 9 meteorological stations from 1960 to 2020 were used.The multiscale moving t-test was applied to capture different rainy season characteristics(including onset time,retreat time,duration,rainfall amount,rainfall intensity,and rainfall days of rainy season)in Ningxia Region.Based on this,the influences of atmospheric circulation,monsoon and sea surface temperature on the rainy season characteristics were explored.Results showed that the onset and retreat of rainy season in Ningxia Region had obvious inter-annual and spatial patterns,and enhanced or weakened anti-cyclone in North Western Pacific reflected the beginning(ending)of the rainy season.Rainfall amount and intensity showed an increased tendency after mutation years.Furthermore,several rainy season characteristics showed a negative correlation with the ENSO region,which meant that warmer sea surface temperature would cause the earlier date of onset and retreat of rainy season,and smaller rainfall amount and rainfall intensity and rainfall days.The research results can provide a reference for exploring the telecorrelation between the rainy season characteristics and sea surface temperature in Ningxia Region.