北太平洋维多利亚模态对淮河流域夏季降水的影响

Impact of the North Pacific Victoria Mode on summer precipitation in the Huaihe River Basin

北太平洋维多利亚模态(Victoria Mode,VM)是北太平洋重要的气候模态,对全球降水和气候有着重要影响。本文使用CN05.1格点化观测数据集资料,研究了春季(2—4月)VM模态与我国淮河流域夏季(6—8月)降水的关系,揭示了其内在的可能机制,并在此基础上建立了一个淮河流域夏季降水预测模型。结果表明,春季VM模态与淮河流域夏季降水存在较强的正相关关系,该相关受ENSO影响有限;春季VM模态可以通过海气相互作用在夏季增强赤道西太平洋上空的异常西风,导致影响淮河流域的气旋性环流异常。气旋性环流异常有利于淮河流域上空丰富的水汽供应和异常上升运动。因此,淮河流域夏季降水量增加。

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.