易文军　石兴琼　梁可　陈曦

摘要    统计张家界市城区1981—2015年逐月暴雨日数，分析暴雨集中期，再利用NCEP 2.5°×2.5°逐6 h分析比湿资料，分析850 hPa上暴雨季节的比湿值变化特征。结果表明，张家界暴雨主要出现在夏季，春季和秋季暴雨有但较少，暴雨集中期在5—9月，大暴雨（≥100 mm）的降水主要集中在6—7月。不同的暴雨季节气温有所变化，故不同暴雨季节的比湿阈值也有所变化，总体来说夏季比湿阈值要比春季和秋季略偏高，春季产生暴雨的水汽条件850 hPa比湿阈值为12 g/kg，夏季产生暴雨的水汽条件850 hPa比湿阈值为13 g/kg，秋季产生暴雨的水汽条件850 hPa比湿阈值为11 g/kg。在同一个季节中，不同的月份比湿阈值也有所区别。

关键词    暴雨日数;水汽条件;比湿阈值;预报应用;湖南张家界

中图分类号    S161.6        文献标识码    A

文章编号   1007-5739（2020）19-0181-04

Study  on  Water  Vapor  Condition  Threshold  for  Rainstorm  and  Its  Forecast  in  Zhangjiajie  City

YI Wenjun 1    SHI Xingqiong 1    LIANG Ke 1    CHEN Xi 2

（1 Meteorological Bureau of Zhangjiajie City in Hunan Province， Zhangjiajie Hunan 427000; 2 Meteorological Bureau of Sangzhi County， Sangzhi Hunan 427100）

Abstract    Based on the monthly rainstorm days from 1981 to 2015 in Zhangjiajie City， the rainstorm concentration period was analyzed， and the specific humidity data by NCEP 2.5°×2.5° for 6 h to analyze the variation characteristics of specific humidity value in rainstorm season at 850 hPa. The results showed that the rainstorm in Zhangjiajie mainly occured in summer， but there were few rainstorms in spring and autumn. The rainstorm concentration period was from May to September， and the heavy rain （≥100 mm） mainly occured from June to July. The temperature varied in different rainstorm seasons， so the specific humidity threshold also changed in different rainstorm seasons.In general， the specific humidity threshold in summer was slightly higher than that in spring and autumn. The specific humidity threshold of 850 hPa in spring was 12 g/kg， that of 850 hPa in summer was 13 g/kg， and that in autumn was 11 g/kg. In the same season， the specific humidity threshold of different months was also different.

Keywords    number of rainstorm days; water vapor condition; specific humidity threshold; forecast application; Zhangjiajie Hunan

暴雨是我国主要气象灾害之一，其常导致山洪暴发、农田渍涝、山体滑坡等灾害，尤其是大范围持续性暴雨和局地特大暴雨，给我国农业生产、农作物生长等带来较严重的危害和损失。张家界市地处武陵山脉腹地、澧水中上游地區，是湖南省三大暴雨中心之一。近年来，随着气象事业的不断发展，广大气象工作者对暴雨开展了大量的分析和研究，在暴雨预报中取得了丰富的经验和方法。黄小玉等[1]利用2002—2004年5—7月15次伴有低空急流暴雨天气过程的常规观测资料进行了分析，归纳总结得出，湖南省汛期暴雨可以分为低槽暴雨和切变线暴雨两大类。叶成志等[2]对“03.7”湘西北特大致洪暴雨过程进行综合分析得出，有组织的多单体风暴活动是这一特大暴雨中心形成的主要原因。……