济阳区短时强降水天气变化特征研究分析

Study and Analysis on the Characteristics of Shortterm Heavy Precipitation Weather Change in Jiyang

通过分析济阳区2008—2018年9处区域和国家级自动气象观测站降水观测资料,研究短时强降水天气的时间和空间分布特征,分析短时强降水年、月、旬、日变化特征、极值变化等。结果表明:(1)近11年来,短时降水出现次数呈增多趋势,2016年和2017年出现短时强降水的日数和站次数最多。(2)1 h降水量≥20 mm短时强降水一般出现在6—8月,7月最多,但是11年来7月短时强降水变化呈减少趋势;1 h降水量≥40 mm的短时特强降水都发生在7—8月。(3)出现短时强降水天气的时段以午后至傍晚居多,夜间次之,上午最少。(4)从空间分布看,11年来出现短时强降水最多的是济阳国家站,其次是位于济阳区西南方位的孙耿街道。(5)出现短时强降水时前24 h水汽压波动6月最大,最大和最小水汽压差值平均12.3hPa,7月次之,8月最小,平均差值仅为4.5 hPa。8月水汽压普遍较高但变化波动小,这也是8月容易出现暴雨的主要原因。

By analyzing the precipitation observation data of nine regional and national automatic meteorological observation stations in Jiyang from 2008 to 2018, the temporal and spatial distribution characteristics of short-term heavy precipitation weather were studied, and the annual, monthly,ten-year, daily change characteristics and extreme value changes of short-term heavy precipitation were analyzed. The results showed that:(1)In recent 11 years, the frequency of short-time heavy precipitation showed an increasing trend, and the number of days and stations with short-time heavy precipitation was the largest in 2016 and 2017.(2)1 hour precipitation≥20 mm short-term heavy precipitation generally appears from June to August, with the most precipitation in July, but the change of short-time heavy rainfall in July showed a decreasing trend in the past 11 years;Short-term exceptionally strong precipitation of 1 hour≥40 mm occurs from July to August.(3)The time period of short-term heavy precipitation weather was mostly from the afternoon to the evening,followed by the night, and the least in the morning.(4)From the perspective of spatial distribution, In the past 11 years, jiyang National Station had the most short-time heavy rainfall, followed by Sungeng Street located in the southwest of Jiyang District.(5) The fluctuation of hydropressure in the 24 hours before the occurrence of short-time heavy precipitation was the largest in June,and the difference between the maximum and minimum hydropressure was 12.3 hPa on average, followed by July and August, with an average difference of 4.5 hPa. In August, the water pressure was generally higher but the fluctuation was small, which was also the main reason why August was prone to heavy rain.