福建省冬季暴雨过程及其环流特征

利用福建省66个气象观测站1960年12月至2008年2月的暴雨资料,分析了福建冬季暴雨的时空特征及主要影响天气系统。结果表明,冬季暴雨主要发生在闽西;福建冬季暴雨主要是南支槽东移、切变线维持和冷空气南下影响所致;冬季暴雨的产生与充沛的水汽、对流不稳定和辐合上升运动密切相关,但大气层结比汛期暴雨要稳定得多;冬季暴雨异常与500 hPa大气环流和赤道中东太平洋海温异常关系密切,它们可能主要通过大气环流的改变引起福建冬季暴雨异常。

Winter Rainstorms and Its Circulation Characteristics in Fujian Province

The rainstorm data of 1960 to 2008 from 66 weather observations in Fujian province are used to analyze the spatial and temporal distribution and main influencing synoptic systems of winter rainstorms.The results show that winter rainstorms appear mainly in the western Fujian.The main influencing systems include the eastward moving south westerly trough,steady shear line,and southward moving cold air;the physical conditions for winter rainstorm formation are correlated with abundant vapor,atmospheric instability,and convergent upward movement,but the stratification of the atmosphere is more stable in winter than those in flood season;the atmosphere circulation at 500 hPa is closely related to sea-surface temperature anomalies around the equatorial middle-eastern Pacific,which may induced the abnormity of winter rainstorms over Fujian through influencing the atmosphere circulation.