强降水事件的判定指标及评估研究  

Evaluation on indicators for heavy precipitation events

作　　者：陈圣劼 张柳 康志明 刘梅[1,3] 田心如[1] CHEN Shengjie;ZHANG Liu;KANG Zhiming;LIU Mei;TIAN Xinru(Jiangsu Meteorological Observatory,Nanjing 210019,China;School of Atmospheric Sciences,Nanjing University,Nanjing 210023,China;China Meteorological Administration Transportation Meteorology Key Laboratory,Nanjing 210019,China)

机构地区：[1]江苏省气象台,南京210019 [2]南京大学大气科学学院,南京210023 [3]中国气象局交通气象重点实验室,南京210019

出　　处：《气象科学》2023年第4期505-514,共10页Journal of the Meteorological Sciences

基　　金：江苏省青年科技人才托举工程(TJ-2022-053);江苏省气象局科研项目(KZ202205,KZ202201,KZ202101,KM201801)。

摘　　要：以江苏1961—2020年夏季(6—9月)强降水事件的监测为例,分析评估了多种强降水事件的判定指标,如以百分位法、Gamma分布法和重现期法为代表的频率匹配阈值法及考虑偏离气候态程度的异常度法。结果表明,由于降水事件的区域差异和季节内变化特征,强(极端强)降水事件判定指标的设计应分区域分时段讨论,且能定量反映降水强度大、相对气候态异常显著且发生概率少(极少)的特点。不同判定方法所强调的强(极端强)降水事件的特点不同,如百分位法Type-Ⅱ强调了降水极值的极少发生,异常度法突出反映大幅度偏离气候态的程度。不同指标所确立的阈值大小也存在明显差别,如对于江苏夏季极端强降水事件的判定,百分位法Type-Ⅱ阈值最高,其次是异常度法,分别相当于20、10 a一遇最大降水量,百分位法Type-Ⅲ和Gamma分布法则相当于5 a一遇最大降水量。在与降水相关的服务工作中,不同地区需制定更详细的地方标准来明确强降水事件的定义,增强服务用语的规范性。Multiple indicators for heavy precipitation events have been evaluated by taking the monitoring of the summertime(June-September)heavy precipitation events over Jiangsu Province for example.Establishing the frequency-matching thresholds by the ways of calculating the percentiles,Gamma cumulative probability and the return periods,and the standardized anomalies associated with the deviation from climatology are the representative methods for the identification of heavy precipitation events.Results show that considering the intraseasonal variation and regional disparity of the precipitation,the indicators for heavy(extremely heavy)precipitation events should be discussed in different regions and periods,as well as can objectively underline the rarely enhanced intensity,the significant abnormality,and the small(extremely small)occurrence probability.Different indicators emphasized different characteristics of the heavy(extremely heavy)precipitation events.For example,the rare occurrence of the extremity of the rainfall amount is underscored by the percentiles method Type-Ⅱ,while the departure far away from the climate state of precipitation is denoted by the standardized anomalies.The difference of the thresholds by the indicators is obvious.For identifying the extreme heavy precipitation events over Jiangsu in summer,the thresholds obtained by the percentiles method Type-Ⅱare the highest and approximately equates to the maximum precipitation with a return period of 20 years.The next is the method of calculating the standardized anomalies with the thresholds equal to a return period of 10 years,while the threshold rainfall by the methods of the percentiles method Type-Ⅲand the Gamma cumulative probability occurs about every 5 years.To unify the expression in the service work,the detailed regional standards of the definition of heavy precipitation events should be further proposed.

关 键 词：强(极端强)降水事件 判定指标 频率匹配阈值 异常度 评估 

分 类 号：P468.024[天文地球—大气科学及气象学]