Statistical analysis of uncertainty in the location of ERA5-Land heavy precipitation extremes
Using the observation data from 665 stations in May-September 1981-2019 in China and the precip-itation 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 precipita-tion 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 loca-tion of the heavy precipitation extremes is informative for the risk and warning areas of extreme precipitation events.
heavy precipitationposition deviationERA5-LandChina
万方数据
维普
