不同风向条件下温州短时强降水统计特征研究

Study on the Statistical Characteristics of Short-time Heavy Precipitation in Wenzhou Under Different Wind Directions

利用2015—2020年7~10月洞头风廓线雷达测风资料和温州345个自动气象站小时降水资料,分析850 hPa高度的各风向和风速条件下,温州短时强降水的统计特征和空间分布特征。结果表明,850 hPa高度上所有风向中以东南(SE)风向条件下温州出现≥20 mm/h的站次数最多。在东风系统影响下,温州出现≥20 mm/h短时强降水时,850 hPa上绝大多数为东东南(ESE)、东南(SE)及南东南(SSE)风,其中以≥20 m/s的ESE风出现短时强降水的站次数最多,而≥50 mm/h短时强降水站次数以16~20 m/s的SE风最多。850 hPa高度上,ESE风条件下,≥20 mm/h短时强降水高频区主要在泰顺、文成、平阳和苍南四县交界处;SE风条件下,高频区包括鹿城、瓯海、瑞安、平阳等四地的西部,苍南西北部、文成全部、泰顺东部和西北部;SSE风条件下,高频区主要在永嘉西部、鹿城和瓯海西部、瑞安西北部和文成东北部。

Based on the wind data of Dongtou wind profiler radar and hourly precipitation data of 345 automatic weather stations in Wenzhou during July-October from 2015 to 2020, the statistical characteristics and spatial distribution characteristics of short-time heavy precipitation in Wenzhou under various wind directions and speeds at 850 hPa were analyzed. The results show that among all the winddirections at 850 hPa, SE wind has the largest number of stations with short-time heavy precipitation at least 20 mm/h(SP). Under the influence of the easterly system, most directions of wind at 850 hPa is ESE, SE and SSE when SP occurs in Wenzhou. ESE wind greater than or equal to 20 m/s has the largest number of stations with SP, while SE wind at 16~20 m/s has the largest number of stations with short-time heavy precipitation greater than or equal to 50 mm/h. Under the condition of ESE wind at 850 hPa, the high frequency area of SP is mainly at the junction of four counties: Taishun, Wencheng, Pingyang and Cangnan. Under the condition of SE wind, the high frequency areas include the west of Lucheng, Ouhai, Ruian and Pingyang, the northwest of Cangnan, all of Wencheng, the east and northwest of Taishun. Under the condition of SSE wind, the high frequency areas are mainly located in the west of Yongjia, Lucheng and Ouhai, the northwest of Ruian and the northeast of Wencheng.