中国区域ERA5-ZTD/PWV精度评估与台风事件响应研究OACSTPCD

Reanalysis data can provide a variety of historical meteorological assimilation products.To evaluate the accuracy of zenith tropospheric delay(ZTD)and precipitable water vapor(PWV)derived from ERA5 datasets of the European Centre for Medium-Range Weather Forecasts over China,the ZTD and PWV derived from the 14 ground Global Navigation Satellite System stations and 89 sounding stations in China during 2017-2019 are used to test the accuracy of ERA5-ZTD and ERA5-PWV.The results show that the accuracy distribution of ERA5-ZTD is uniform except for the sites in Qinghai-Tibet region,and the mean Bias,RMSE and STD of ERA5-ZTD are-6.3 mm,19.3 mm and 17.5 mm,respectively.The accuracy distribution of ERA5-PWV shows a trend of higher accuracy in the western interior and lower accuracy in the southeast coast,with the mean Bias,RMSE and STD of 0.3 mm,2.9 mm and 2.7 mm,respectively.In addition,the temporal and spatial distributions of ZTD and PWV during the super typhoon Lekima's period in 2019 are studied,and a method based on arrival time difference of water vapor is proposed to quantitatively estimate the water vapor moving velocity of the typhoon.The results show that spatial distributions of ZTD and PWV are similar during the typhoon's period,and the moving directions of ZTD and PWV are both consistent with the direction of the typhoon's path.The estimated mean moving speed of water vapor is 12.4 km/h,which is very close to the average moving speed of typhoon 16.1 km/h.The above studies fully show that ERA5-ZTD/PWV has a high accuracy in China,and ZTD and PWV can be used as impor-tant meteorological factors to provide important reference value for typhoon early warning and forecast research.