In order to further improve the detection accuracy of atmospheric water vapor information for short-term extreme weather warning and forecast by global navigation satellite systems (GNSS),the paper studied the response of BeiDou navigation satellite system (BDS) to rainfall events of different intensities in Tianjin:several continuous operating reference stations (CORS) in Tianjin were selected,based on the multiple rainfall events in Tianjin from August 1 to 23,2023,BDS data were used to invert atmospheric precipitable water vapor (PWV),and its response mechanism to different intensity of rainfall was discussed.Results showed that,using PWV detected by the fifth generation atmospheric reanalysis dataset (ERA5) as reference values,the standard deviation (STD) and root mean square (RMS) of BDS PWV would be both less than 2.86 mm,which could be equivalent to the accuracy of PWV inverted by global positioning system (GPS);moreover,before rainfall of different intensity,PWV would increase rapidly and sharply,and its increment would be positively correlated with rainfall intensity;furthermore,the PWV duration increase threshold of 10 h and its increment threshold of 20 mm could be used to effectively forecast rainfall of different intensification in Tianjin,which would be of great significance for the early warning of heavy precipitation,especially extreme heavy precipitation events.
BeiDou navigation satellite system (BDS)Tianjin continuous operation reference stations (CORS)zenith total delay (ZTD)precipitable water vapor (PWV)precipitation