1961-2015年安徽省小时降水变化特征与极值分布

摘要

运用安徽省79个国家站1961-2015年逐小时降水资料,结合多种数理统计方法分析近55年来安徽省小时降水的分布及变化特征,并基于广义极值分布研究小时降水的概率分布及重现期,旨在为当前暴雨洪涝灾害风险预警以及实时气象防灾减灾等业务提供技术支撑.结果表明:安徽省最大lh、3h、6h、12h降水量空间分布型基本一致,极端强降水局地性特征明显,且主要发生在梅雨期及台风引发的强降水;不同等级小时降水日变化特征存在明显差异,特大暴雨和大暴雨日变化呈单峰型分布,而其它等级的小时降水均呈双峰型分布,全省绝大部分地区的小时强降水存在增多趋势;全省62％台站小时雨量服从于极值Ⅱ型分布,其余38％台站服从于极值Ⅲ型分布,8个典型代表站概率密度分布重尾均在右侧,属于右偏态分布,其中安庆、宿州和合肥呈现“尖峰厚尾”的分布特征,出现小时极端强降水的概率相对较大,各典型代表站不同重现期小时雨量差异明显,但与其空间分布没有明显的相关性.%By using hourly precipitation data of 79 national meteorological stations from 1961 to 2015 in Anhui province,and combining with a variety of mathematical statistical methods,We analyze the distribution and variation characteristics of hourly precipitation in recent 55 years in Anhui province,and study the probability distribution and return period of hourly precipitation based on generalized extreme value distribution,and aim to provide the technical support for current services including flood disaster risk early warning and real-time meteorological disaster prevention and mitigation.The results show that spatial distributions of maximum precipitation of 1 hour,3 hours,6 hours and 12 hours are basically similar,extreme heavy precipitation have obvious local characteristics and have mainly occurred in Meiyu and typhoon periods.There are significant differences in the diurnal variation characteristics of hourly precipitation at different levels,the torrential rain and downpour show the single peak distribution,but other levels of hourly precipitation show the double-peak distribution,and also there is an increasing trend of hourly precipitation in most parts of Anhui province.The hourly precipitation of 62％ stations follow the probability distribution of extreme value type Ⅱ,the other 38％ stations follow type Ⅲ.For the 8 typical representative stations,the heavy tailed of probability density distribution are all on the right side,and belong to the right skewed distribution.Anqing,Suzhou and Hefei are as the distribution characteristics of "high peak and fat tail",the probability of occurrence of extreme heavy precipitation is relatively large.In different return periods,the hourly precipitations of the typical stations are significantly different,but there is no obvious correlation with its spatial distribution.