北太平洋维多利亚模态对淮河流域夏季降水的影响OACSTPCD

The Victoria Mode(VM)of the North Pacific is a significant climatic mode,exerting a profound influence on global precipitation and climate.This study employed the CN05.1 gridded observational dataset to explore the relationship between the VM mode during the spring(February-March-April,FMA)and the summer(June-July-August,JJA)precipitation over Huaihe River Basin in China,unraveling potential underlying mechanisms.On this basis,a predictive model for JJA precipitation in the Huaihe River Basin was developed,utilizing the FMA VM model for forecasting.The findings reveal a strong positive correlation between the FMA VM mode and the subsequent JJA precipitation in the Huaihe River Basin,with limited influence from ENSO.Further mechanistic analysis indicates that the FMA VM mode enhances the zonal sea temperature gradient in the tropical Pacific by jointly influencing negative sea temperature anomalies in the Northwest Pacific and positive anomalies in the Northeast Pacific subtropical region,which intensifies the anomalous westerlies over the western Pacific,leading to cyclonic circulation anomalies affecting the Huaihe River Basin.These anomalies facilitate substantial moisture transport to the land,ensuring ample water vapor supply for the region.Additionally,lower-level convergence and upper-level divergence create anomalous ascending movements in the Huaihe River Basin,thus increasing JJA precipitation.Utilizing comprehensive data from 1979 to 2020,a linear regression model based on VM indicates its effectiveness as a predictive factor for JJA precipitation in the Huaihe River Basin.