江西省极端降水分类及特征分析

利用多种观测及再分析资料对江西省极端降水过程进行统计分类和天气学分析。采用百分位法、广义极值法对比计算江西省极端降水强度阈值标准，分析江西省极端降水事件的空间分布特征，筛选出2010—2019年江西省极端降水的典型过程，并进行天气学成因分析。结果表明：1） 江西省各站极端降水强度阈值空间分布差异较大，由西南向东北逐步增加，具有非常明显的地域性特征；2） 江西省典型极端降水过程发生在夏季（6—8月），主要分为梅雨锋、强台风、西北气流类；3） 江西省梅雨锋类极端降水占典型极端降水过程的70%，该类极端降水具有稳定的大尺度环流形势，主要表现为南亚高压北跳至25°N以北，阻塞高压异常偏强，东北冷涡发展，副热带高压与大陆高压相结合，配合天气尺度稳定的切变线以及异常的西南暖湿气流，形成持续的水汽输送及异常的垂直上升运动中心。

Classification and characteristics analysis of extreme precipitation in Jiangxi Province

Based on various observation and reanalysis data, the statistical analysis and synoptic study of extreme precipitation process in Jiangxi were carried out. The percentile method and generalized extreme value method were used to calculate the threshold standard of extreme precipitation intensity in Jiangxi Province. The spatial distribution characteristics of extreme precipitation events in Jiangxi Province were analyzed, and the typical extreme precipitation processes in Jiangxi Province from 2010 to 2019 were selected for synoptic analysis. The results showed that: 1) The spatial distribution of extreme rainfall intensity thresholds at each station in Jiangxi presented significant differences, increased gradually from southwest to northeast, with particular obvious topographic characteristics. 2) The typical extreme precipitation process in Jiangxi Province occurred in summer (June, July, August), including three types: Meiyu front, strong typhoon and northwest airflow. 3) The Meiyu front extreme precipitation accounted for 70% of the typical process in Jiangxi Province. The Meiyu front extreme precipitation exhibited a stable large scale circulation situation: the South Asian high jumped northward to the north of 25°N, the anomalous strong blocking high, the development of the northeast cold vortex, and the combination of the subtropical high and the continental high. In addition, it cooperated with the stable shear line at the synoptic scale and the anomalous southwest warm and humid air flow in the lower and boundary layers, resulting in continuous water vapor transport and anomalous vertical ascending motion center.