基于多套卫星资料的ERA5全球小时降水频率评估  

Evaluation of the global hourly precipitation frequency in ERA5 using multiple satellite datasets

作　　者：李蓬生 李晓峰 杨崧[1,2] LI Pengsheng;LI Xiaofeng;YANG Song(School of Atmospheric Sciences,Sun Yat-sen University,and Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519000,China;Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies,Zhuhai 519000,China)

机构地区：[1]中山大学大气科学学院/南方海洋科学与工程广东省重点实验室(珠海),广东珠海519000 [2]中山大学广东省气候变化与自然灾害研究重点实验室,广东珠海519000

出　　处：《大气科学学报》2024年第2期249-259,共11页Transactions of Atmospheric Sciences

基　　金：国家自然科学基金资助项目(42088101,42175026);高原大气环境四川省重点实验室开放课题(PAEKL-2022-K08);南方海洋科学与工程广东省实验室(珠海)创新团队建设项目(316323005);广东省气候变化与自然灾害重点实验室(2023B1212060019)。

摘　　要：最近发布的新一代全球再分析资料集ERA5,提供了全球小时降水再分析值,为全球小时降水研究提供又一个数据参考。然而,目前针对ERA5小时降水频率的评估工作还较为有限。本研究采用多套全球卫星观测小时降水对ERA5小时降水的频率进行了评估。对比分析发现:尽管ERA5总降水量与卫星资料出现较好的一致性,但ERA5的小时降水频率约为卫星资料的2~3倍,呈现系统性偏高。进一步分析表明,这主要是由于ERA5大大高估了中、低强度降水事件的数量。其中,ERA5对弱降水频率的高估尤为明显,平均可达卫星降水频率的6倍;此外,ERA5对海洋降水频率的高估程度也大于陆地。ERA5小时降水频率的系统性高估问题对相关研究的潜在影响,尚在进一步评估中。The newly released ERA5 reanalysis dataset by the ECMWF provides hourly precipitation reanalysis values,adding another reference for global hourly precipitation research.However,current evaluations of ERA5 hourly precipitation are limited,focusing more on monthly and daily precipitation assessments or hourly precipitation within restricted areas.Few studies address global-scale assessments of hourly precipitation.Motivated by this gap,we assess the global hourly precipitation frequency of ERA5.Sparse station-observed hourly precipitation data,particularly over open oceanic and remote inland areas,limits its usefulness for global-scale assessment of ERA5 reanalysis precipitation data,despite its presumed accuracy over satellite estimates or precipitation reanalysis data.Consequently,we employ four satellite datasets—GPM,GSMaP-M,GSMaP-G,and CMORPH—to evaluate hourly precipitation frequency of ERA5 in this study.We analyze the spatial distribution of climatological annual total precipitation and precipitation frequency in ERA5 and the four satellite datasets.Additionally,we examine the error sources of hourly precipitation frequency of ERA5 by evenly dividing precipitation events from the 5 datasets into ten intensity bins based on the hourly precipitation intensity percentiles.We then compare precipitation frequency differences among different regions,including tropical and extra-tropical areas,as well as marine and land areas.The main findings are as follows:1)the magnitude and spatial pattern of climatological annual total precipitation of ERA5 close align with the four satellite datasets,indicating ERA5 effectively represents total precipitation.2)The climatological hourly precipitation frequency of ERA5 is 2-3 times higher than that of satellite data,suggesting a systematic error in the hourly precipitation frequency of ERA5 compared to satellite estimates,or an overestimation of average precipitation frequency of ERA5.3)The overall overestimation of hourly precipitation frequency of ERA5 mainly stems from

关 键 词：小时降水 降水频率 卫星降水 ERA5 极端降水 

分 类 号：P412.27[天文地球—大气科学及气象学] P426.6