Coordinated Variation of Precipitable Water Vapor and Rainfall during Typhoon

Global Navigation Satellite System-derived Precipitable Water Vapor (GNSS-PWV) has been applied in numerous meteorological researches due to its high accuracy and all-weather support. This paper explores the coordinated variation characteristics between the PWV and actual precipitation during typhoon "Chanthu." The PWV series, from ten stations of Shanghai Continuously Operating Reference Stations (SHCORS) during Sep. 10th to 14th, 2021, were retrieved by real-time Precise Point Positioning (PPP) technology. We also collected the rainfall records from eleven meteorological stations during the same period. The results show that PWV content was significantly correlated with precipitation, i.e., PWV initially surged before rainfall, then remained stable during rain, and finally fell back to the normal level after rain. Additionally, the spatial changes of PWV could also reveal the water vapor (WV) transport path during the typhoon. It suggests that real-time PWV has the potential capacity for extreme precipitation warnings. The above findings indicate that the CORS system can equip the rainfall warning module to expand its further service field in the future.