Investigating the ERA5-Based PWV Products and Identifying the Monsoon Active and Break Spells with Dense GNSS Sites in Guangxi, China

Precipitable water vapor (PWV) with high precision and temporal resolution estimated by Global Navigation Satellite System (GNSS) is widely used in atmospheric research weather forecasting. However, most previous works are not consensual concerning the characteristics of PWV at different time scales identification active break spells during summ er monsoon climate Guangxi, China. Taking radiosonde (RS) observations as reference, a strong correlation (R > 0.97) exists between GNSS RS mean root square error (RMSE) 2.68 mm. The annual, seasonal, monthly, diurnal variations three years (2017, 2018 2020) over Guangxi were comprehensively investigated using 104 stations fifth-generation European Centre for Medium-Range Weather Forecasts (ECMWF) Atmospheric Reanalysis (ERA5). annual bias RMSE ERA5 −1.04 mm 2.63 mm, respectively. monthly range −0.77 to 3.87 1.32 4.45 daily −1.41 1.07 1.11 5.02 Additionally, adopted average standardized rainfall anomaly criteria also identified 7/7/3 5/3/7 summer (June–September) from 2017 2020, During three-year period, amplitude ranges varied 1.41 2.49 0.69 5.4 0.88 while 2.45 6.76 1.66 8.17 1.48 2.99 results show superior performance compared maximum, minimum occurrence vary slightly season topography stations. Despite temperature primarily exhibiting negative rainfall, acting dampener, positive remains evident rainfall. Therefore, densely distributed exhibit excellent capabilities quantifying facilitating real-time monitoring small medium-scale phenomena.