安顺市大暴雨的时空分布特征与物理量分析

Spatial and Temporal Distribution Characteristics and Physical Quantity Analysis of Heavy Rainstorm in Anshun

利用2009—2019年安顺市6个国家站和77个区域站的逐日和逐小时降水资料、Micaps资料,对安顺市大暴雨的时空分布特征及物理量进行分析,结果表明:安顺市年平均大暴雨日数为10.1 d,年平均影响范围为54.1站次,5—9月是大暴雨出现的集中期,6月大暴雨出现频次最高,影响范围最广,大暴雨的主要发生时段和最强影响时段出现在夜间到早晨;区域性大暴雨比局地性大暴雨出现时间晚,结束时间早,6月是区域性大暴雨和局地性大暴雨出现最多的月份,5—7月局地性大暴雨出现的频率最高;安顺主要出现单日大暴雨,持续2 d以上的大暴雨只出现过16次;大暴雨总日数的空间分布有两个高频区和两个低频区,总量的空间分布与总日数基本一致,强度的空间分布呈南强北弱,总站次的空间分布呈南多北少;在5月预报大暴雨天气时要更注重分析T 85和T 75,6—7月产生大暴雨时对能量和中低层的水汽含量的要求高于其它月份。

Using the daily and hourly precipitation data and Micaps data of 6 national stations and 77 regional stations in Anshun city from 2009 to 2019,the spatial and temporal distribution characteristics and physical quantities of heavy rainstorms in Anshun were analyzed.The results show that the annual average number of days of heavy rainstorms in anshun was 10.1 d,and the annual average impact range was 54.1 stations.From May to September,heavy rainstorms occur in a concentrated period.In June,heavy rainstorms occur with the highest frequency and the widest impact range.The main period of heavy rainstorms and the period of the strongest impact occurred in the night to morning;Regional heavy rainstorms appear later and end earlier than local heavy rainstorms.June is the month with the most regional heavy rainstorms and local heavy rainstorms,and the frequency of local heavy rainstorms is the highest from May to July.In Anshun,there were mainly one-day heavy rainstorms,and only 16 heavy rainstorms lasting more than 2 d occurred.The spatial distribution of the total number of heavy rainstorm days has two high-frequency regions and two low-frequency regions,and the spatial distribution of the total rainfall is basically consistent with the total number of heavy rainstorm days.Not only the spatial distribution of rainfall intensity is strong in the south and weak in the north,but also the spatial distribution of the number of heavy rainstorm stations is more in the south and less in the north.In particular,more attention should be paid to the analysis of T85 and T75 when severe rainstorms are forecast in May.In addition,the requirements for energy and moisture content in the middle and lower layers are higher than those in other months when heavy rainstorms occur in June and July.