【摘要】 利用1961~2016年湖南省内88个气象台站逐日降水资料和美国国家环境预测中心(NCEP)及国家大气研究中心(NCAR)再分析资料,根据区域持续性暴雨定义,统计分析了湖南汛期发生区域持续性暴雨典型环流型特征及其与首日暴雨落区配置关系.结果表明:(1)湖南汛期发生区域持续性暴雨典型环流型有两槽一脊、两槽两脊、两脊一槽、纬向波动、台风低压和多涡旋型6类;(2)区域持续性暴雨主要发生在6、7月,其次是5、8月,4月和9月发生概率较小,各类环流型区域持续性暴雨日发生累计频次空间分布特征各异;(3)区域持续性暴雨典型环流型类内500hPa中高纬具有相似共性,均有利于持续引导北方冷空气南下至湖南,但因低纬西太平洋副热带高压强度与形态配置不同,低层850hPa西南季风北伸范围存在差异,导致区域持续性暴雨过程首日暴雨落区南北、东西空间差异明显.更多还原

【Abstract】 Based on daily rainfall data and the NCEP/NCAR reanalysis data from 1961 to 2016,and according to the definition of regional persistent torrential rain(RPTR),features of typical circulation pattern of RPTR during the flood season in Hunan province and their relation to the distribution of firstday precipitation area were statistically analyzed.Results are as follows:(1)RPTR often occurs in six major circulation patterns,namely,two-trough-one-ridge,two-trough-two-ridge,two-ridge-one-trough,zonal fluctuation,typhoon depression and mutil-vortex;(2)RPTR occurs mainly in June,July,followed by May and August,and the probability of occurrence in April and September is small.Besides,the spatialdistribution of RPTR cumulative frequency varies in different circulation patterns;(3)Similar characteristics of circulation at 500 hPa are found in the middle-high latitude,which are conducive to the southwards moving of northern cold air to Hunan.However,due to the different intensities and morphological configurations of low latitude of the West Pacific subtropical high,the northern extension of southwest monsoon at 850 hPa varies accordingly,resulting in significant difference in torrential rainfall area on the first day.更多还原