空间分辨率对中国夏季降水时空演变特征的影响OACSTPCD

Based on the monthly precipitation observation data of 160 stations of National Climate Center(R160)and 2 314 stations of national surface meteorological observatory(R2314)from 1979-2021,by using EOF decomposition and correlation analysis,the spatio-temporal characteristics of summer precipitation variation and its physical connection with ocean and atmosphere factors were studied respectively,meanwhile the possible reasons were discussed.Results show that the spatio-temporal characteristics of precipitation variation in northwestern China,Tibetan Plateau and other regions are distorted by the leading EOF modes due to their extremely sparse distribution of stations.In addition,its low spatial resolution would lose the signal of variation characteristics in local heavy rainfall and reduce interannual climate variability in the central and eastern China.In contrast,the leading mode of R2314 can reflect the spatio-temporal evolution characteristics of precipitation in China more realistically,especially in the Yangtze-Huaihe Rivers region where extreme precipitation occurs frequently and in the mountainous areas where precipitation is greatly affected by local terrain,the evolution of spatial distribution and the temporal coefficient are more different from those of R160.Moreover,the association between abnormal variation of R2314 and forcing signals such as ENSO,western Pacific subtropical high and Tibetan Plateau snow cover are more significant.