冷涡背景下江苏极端短时强降水特征分析

Characteristics of Extreme Short-Time Severe Precipitation in Jiangsu Province under the Background of Cold Vortex

摘要: 通过对近10年冷涡背景下江苏省极端短时强降水的统计分析，结果表明：极端短时强降水频次呈缓慢上升的趋势，主要发生在6~8月，其中午后至傍晚时段内发生次数最多，后半夜至中午时段少发；空间分布上有多个高值中心，最大位于连云港到盐城北部，其次沿江和沿淮一线也是短时强降水的多发区。南涡、中间涡和北涡都能产生极端短时强降水，但以中间涡和北涡为主。南涡下降水主要发生在冷涡的南或东南方向，中间涡和北涡下降水发生在冷涡的西南、南或东南。冷涡各个阶段都可产生短时强降水，其中发展和成熟阶段的强降水频次占总数的62.8%。冷涡对江淮地区强对流的影响，主要是提供有利的环流背景引导冷空气南下，而低层偏南气流向影响区输送暖湿气流，高空干侵入叠加在低层暖湿空气之上，较强的位势不稳定导致雷暴、短时强降水和冰雹等强对流天气的发生。

Abstract: According to the statistical analysis of extreme short-time severe precipitation in Jiangsu Province under the background of cold vortex in recent 10 years, the results show that the frequency of extreme short-time severe precipitation increased slowly, and happened mainly from June to August, which the frequency was the most from afternoon to evening and less from late midnight to noon; there were several high-value centers in spatial distribution, the largest located from Lianyungang to the north of Yancheng, followed by the line along the Yangtze River and the Huaihe River, which were also prone to short-timesevere precipitation. The vortex in the south, the middle and the north can produce extremely short-time severe precipitation all, but the vortex middle and north were the main ones. The precipitation under the south vortex mainly occurred in its south or southeast area, and the precipitation under the middle and the north vortex occurred in its south-west, south or southeast area. All stages of the cold vortex can produce short-time severe precipitation, the frequency in the development and maturity stages accounted for 62.8% of the total. The influence of cold vortex on severe convection in Jianghuai region mainly provided a favorable circulation to guide the cold air southward, while the low-level airflow transported warm and humid air from the south to the affected area, the high-level dry air superimposed on the low-level warm and humid air, and the strong potential instability resulted in the occurrence of severe convective weather such as thunderstorm, short- time severe precipitation and hail.