福建省冰雹时空分布与天气气候特征分析

Spatiotemporal distribution and weather characteristics of hail in Fujian Province

利用1960-2008年高空常规探测资料和福建省内各台站冰雹的观测资料,分析了福建省冰雹的时空分布和春季、夏季降雹的天气气候特征。结果表明:福建省20世纪80年代中期到90年代初期为冰雹多发期,90年代中期至今呈明显减少趋势。冰雹发生的季节分布呈双峰型,高发期在3—5月,次高发期在7—9月。空间分布表现为中北部多,南部少;山区多,平原少;内陆多,沿海少。冷空气与强暖湿气流相遇是春季降雹的主要原因,主要天气型(850hPa)为低涡冷切适中、冷切适中、冷切偏南、冷切偏西、低涡冷切偏西等,冷式切变和低空西南急流是触发大范围冰雹过程最重要的天气条件。下垫面被迅速加热,快速升温,午后局地上空形成强辐合区是夏季降雹的主要原因,主要天气型(500hPa)为副热带小高压和副热带高压边缘。

Based on the radiosonde data and hail records in Fujian Province between 1960 and 2008, the spatial and temporal features of hail disaster and weather and climatic characteristics in Fujian during spring and summer were analyzed. The results show that hailing days reached the peak between mid 1980＇s and the early 1990s, and then show a decreasing trend from the mid 1990＇s. The seasonal change of hail presents a typical bimodal pattern with the higher peak appears at March to May, and the other appears at July to September. The hail is more likely to occur in the Middle and North parts than in the south, more likely to occur in mountains than in the plain, and more likely to occur in midland than in littoral. The hails occur in spring might be caused by the meeting of cold air and strong warm moist air, when the main weather patterns （850hPa） in Fujian are： moderate vortex and cold shear, moderate cold shear, southward deflection cold shear, westward deflection cold shear and westward deflection vortex and cold shear; cold shear and strong low - level southwest jet are the important condition inducing widespread hail. Main weather condition causing hail in summer is local strong convergence in the afternoon, of which the synoptic situations （500hPa） are subtropical high pressure and the edge of subtropical high.