Circulation Characteristics and Drivers of Persistent Cold Rain and Snow Events in Southern China
ZHU Hua
ZHANG Haitao
ZHOU Chaorong
Abstract：Based on conventional observational data and NCEP reanalysis data,this study defines and identifies persistent cold rain and snow events(PCRSEs)in southern China during 1960-2019.The results show that the large-scale trough-ridge systems in mid-to-high-latitude Eurasia are the key circulation features of these events,which can be categorized into three types:the single blocking transverse trough,two-trough-one-ridge,and zonal circulation.The first two types are characterized by blocking highs or ridges near the Ural Mountains or Lake Baikal,respectively.Among them,the single blocking transverse trough type exhibits the strongest upper-tropospheric trough-ridge structure,a westward-displaced cold air pathway,and the most intense surface cold high,leading to the lowest average temperatures,longest durations,and widest impact areas observed during PCRSEs in southern China.These stable upper-tropospheric trough-ridge patterns,combined with strong surface cold air advection and warm-moist water vapor transport,collectively drive PCRSE occurrence in southern China.Correlation analysis reveals that the 500 hPa polar vortex,mid-to-high-latitude Eurasian ridges,Tibetan Plateau troughs,the Siberian High,and equatorial central-eastern Pacific sea surface temperature anomalies are key drivers of the interannual variability of winter PCRSEs in southern China.
Keywords：southern China cold rain and snow eventssynoptic classificationcirculation characteristicscorrelation analysisinfluencing regions
Publication Date：2025-06-30
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：14( 413-426 )