采用北斗PPP-B2b服务的大气可降水量反演及香港地区暴雨过程分析

Prelipitable water vapor inversion using BeiDou PPP-B2b service and analysis of heavy ra infall process in Hong Kong region

北斗三号卫星导航系统精密单点定位服务(PPP-B2b服务)通过卫星B2b信号向用户发送改正信息,摆脱了对外部通信的依赖,为实时反演大气可降水量(PWV)提供了新的技术途径。本文利用试验分析了PPP-B2b服务反演PWV的精度。试验结果表明,利用PPP-B2b服务反演结果与采用CODE事后精密星历产品的差值RMS为3.70 mm,STD为3.61 mm,与ERA5再分析数据差值的RMS和STD分别为4.80和4.07 mm,与探空结果差值的RMS和STD分别为3.75和7.16 mm,验证了采用PPP-B2b服务的PWV反演结果具有较好的精度。最后,通过分析香港地区暴雨过程的实际降水量与PWV反演结果之间的相关性,初步验证了BDS PPP-B2b服务用于暴雨灾害短时预警的可行性。

The precision single point positioning service(PPP-B2b service)of BDS-3 sends correction information to the user through the satellite B2b signal,which is free from the dependence on external communication,and provides a new technological way for real-time inversion of precipitable water vapor(PWV)in the atmosphere.In this paper,the accuracy of PWV inversion using PPP-B2b service is analysed experimentally,and the experimental results show that the difference between the inversion results using PPP-B2b service and those using the CODE hindcast precision ephemeris product is 3.70 mm in RMS and 3.61 mm in STD,and the differences with the ERA5 reanalysis data are 4.80 mm in RMS and 4.07 mm in STD,and the differences with the sounding results are 4.80 mm and 4.07 mm in STD,respectively.The RMS and STD of the difference with the ERA5 reanalysis data are 4.80 mm and 4.07 mm,and the RMS and STD of the difference with the sounding results are 3.75 mm and 7.16 mm,respectively,which verifies that the PWV inversion results using the PPP-B2b service have a good accuracy.Finally,by analysing the correlation between the actual precipitation and the PWV inversion results of the rainstorm process in Hong Kong region,the feasibility of BDS PPP-B2b service for the short-term early warning of rainstorm disasters is preliminarily verified.