干旱气象 ›› 2020, Vol. 38 ›› Issue (6): 937-946.

• 论文 • 上一篇    下一篇

2019年6—7月两湖流域雨情异常成因分析

王孝慈,李双君,孟英杰   

  1. 武汉中心气象台,湖北武汉430074
  • 出版日期:2020-12-31 发布日期:2021-01-06
  • 通讯作者: 李双君(1984— ),男,硕士,高级工程师,主要从事短时临近预报预警相关工作. E-mail: dreamom@163.com。
  • 作者简介:王孝慈(1986— ),女,硕士,高级工程师,主要从事水文气象预报相关工作. E-mail: wxc327@163.com

Analysis on Causes of Abnormal Rainfall in the Two-Lake Basin from June to July in 2019#br#

WANG Xiaoci, LI Shuangjun, MENG Yingjie   

  1. Wuhan Central Meteorological Observatory, Wuhan 430074, China
  • Online:2020-12-31 Published:2021-01-06

摘要: 运用水库汛情资料和民政厅灾情数据,分析2019年6—7月湘赣地区灾情、汛情特征。基于长江流域国家气象观测站雨量资料,NCEP/NCAR再分析资料及长江中游雷达组合反射率因子SWAN拼图产品,分析2019年梅雨期两湖流域雨情异常的主要原因。结果表明:(1)高层南压高压和西风急流季节性北跳提前,中层副热带高压北跳提前,2次短暂的北跳中伴有长时间的南落,低层夏季风提前北推至25°N,高、低层大气环流系统共同作用,导致2019年6—7月雨带稳定维持在湘赣地区。同时从低层到高层源自华南地区持续的水汽输送带,为两湖流域的降水提供了充沛的水汽。(2)2019年6—7月梅雨锋稳定维持在湘赣中游,其间两湖流域爆发了5次强降水过程,高温、高湿、高能的环境诱使大范围稳定降水带中多伴随中小尺度对流系统,短时强降水等对流活动频发,进一步增大了分区面雨量,月累计面雨量创历史新高。

关键词: 两湖流域, 副热带高压, 南压高压, 灾害性强降水, 异常雨情

Abstract: The flood information of reservoirs and disaster data from civil affairs departments were used to analyze characteristics of disaster and flood situation in Hunan-Jiangxi region from June to July in 2019. Based on rainfall data from national meteorological observation stations in the Yangtze River Basin, NCEP/NCAR reanalysis data and radar combined reflectivity factor of Swan mosaic product in the middle reaches of the Yangtze River, the main causes of rainfall anomaly in the Two-Lake Basin during the Meiyu period in 2019 were analyzed. The results are as follows: (1) From the perspective of the large-scale circulation background anomaly, the seasonal northward jump of south Asia high and westerly jet in high level was advanced, the northward jump of subtropical high in middle-level was also earlier, during the two temporary northward jump, there was a long-term southward fall, and the summer monsoon in low-level was pushed northward to 25°N in advance. The interaction of the high-low-level atmospheric circulation system resulted in the stable rain belt in Hunan-Jiangxi region from June to July in 2019. At the same time, the continuous water vapor transport belt from the lower to the upper layer in South China provided abundant water vapor for precipitation in the Two-Lake Basin. (2) From the perspective of occurrence frequency of medium and small scale severe convective weathers, the Meiyu front remained stably in the middle reaches of Hunan and Jiangxi provinces from June to July in 2019. During this period, five heavy precipitation processes broke out in the Two-Lake Basin. The environment of high temperature, high humidity and high energy induced the large-scale stable precipitation belt accompanied with the meso-micro scale convective systems, short-term heavy rainfall and other convective activities occurred frequently, which further increased the area rainfall and made the monthly accumulated area rainfall to reach a record high.

Key words: Two-Lake Basin, subtropical high, south Asia high, disastrous heavy rainfall, abnormal rainfall