ERA5-Land强降水极值位置不确定性的统计分析  

Statistical analysis of uncertainty in the location of ERA5-Land heavy precipitation extremes

作　　者：王子晴 董雪晨 龚道溢[1,2,3,4] Wang Ziqing;Dong Xuechen;Gong Daoyi(State Key Laboratory of Earth Surface Processes and Resource Ecology,Beijing Normal University,Beijing,100875,China;Key Laboratory of Environmental Change and Natural Disasters of Chinese Ministry of Education,Beijing Normal University,Beijing 100875,China;Academy of Disaster Reduction and Emergency Management,Ministry of Emergency Management and Ministry of Education,Beijing 100875,China;Institute of Disaster Risk Science,Faculty of Geographical Science,Beijing Normal University,Beijing 100875,China)

机构地区：[1]北京师范大学地表过程与资源生态国家重点实验室,北京100875 [2]北京师范大学环境演变与自然灾害教育部重点实验室,北京100875 [3]应急管理部-教育部减灾与应急管理研究院,北京100875 [4]北京师范大学地理科学学部灾害风险科学研究院,北京100875

出　　处：《地理科学》2024年第10期1849-1859,共11页Scientia Geographica Sinica

基　　金：国家重点研发计划项目(2020YFA0608201)资助。

摘　　要：利用中国1981—2019年5—9月665个台站的观测资料以及全球降水观测计划(Global Precipitation Measurement,GPM)反演的降水格点资料,针对东部地区97个台站224个强降水事件(日降水量超过250 mm),统计了0.1°空间分辨率的ERA5-Land再分析资料中降水极值位置和降水量的偏差。结果表明:①在以台站为中心的9×9网格的矩形区域内存在强降水极值中心的个例有123个(占总个例数的54.9%),其落点位于站点所在网格及相邻网格的有45个(占比36.6%),偏离的距离在4个网格之内的则达到119个(占比96.7%),即落点偏差绝大多数在40 km内。从方位上看,主要的偏离方位是偏北(占比30.1%),这证明了模拟强降水极值中心的落点偏差大多数没有超出中尺度的范围,且普遍偏北;② GPM反演降水中约35%个例的站点位于强降水极值中心所在网格或相邻网格内,存在极值中心的68场强降水对应的ERA5-Land极值中心偏差主要集中在4个网格范围内(占比94.1%),且主要偏北(占比31.7%);③如果考虑强降水极值中心位置的偏差对降水进行订正,则能够减少ERA5-Land降水量偏差37.7 mm(12.6%),这证明了考虑强降水位置偏差,能够在考虑模拟强降水强度偏弱的同时,进一步减少预报误差。强降水极值位置的不确定性,对于极端降水事件的风险及预警范围有参考意义。Using the observation data from 665 stations in May-September 1981—2019 in China and the precipitation grid data from the Global Precipitation Measurement(GPM)inversion,for 224 heavy precipitation events(daily precipitation exceeding 250 mm)at 97 stations in the eastern region,the deviation in the location of precipitation extremes and the precipitation amount in the ERA5-Land reanalysis data with 0.1 degree spatial resolution were counted.The results show that:1)There are 123 cases(54.9%of the total cases)of heavy precipitation extreme centers in the rectangular area of 9×9 grid centered on the station,45 cases(36.6%)of which have their fallout points located in the grid where the station is located and the adjacent grids,and 119 cases(96.7%)of which have their deviation within 4 grids,and the majority of the predicted precipitation extreme centers are within 40 km.In terms of orientation,the predominant deviation is toward the north(30.1%),indicating that most of the fallout deviation of the simulated extreme precipitation centers do not beyond the mesoscale range and tend to be northward;2)Approximately 35%of the stations in the GPM inversion precipitation are located in the grid where the extreme center of heavy precipitation is located or in the adjacent grid,and the deviation from the ERA5-Land extreme center corresponding to the 68 heavy precipitation events with the existence of extreme centers are mainly concentrated within 4 grids(94.1%of the total)and mainly to the north(31.7%of the total);3)If the precipitation is revised by considering the deviation of the location of the extreme center of heavy precipitation,it is able to reduce the ERA5-Land precipitation deviation by 37.7 mm(12.6%),which proves that considering the deviation of the location of heavy precipitation can further reduce the forecast error while taking into account the underestimation of simulated precipitation intensity.The uncertainty in the location of the heavy precipitation extremes is informative for the risk and warning areas

关 键 词：强降水 位置偏差 ERA5-Land 中国 

分 类 号：P426.6[天文地球—大气科学及气象学]