China Coastal GNSS Network: Advancing Precipitable Water Vapor Monitoring and Applications in Climate Analysis

Abstract. The Global Navigation Satellite System (GNSS) offers precise, continuous monitoring of atmospheric water vapor, essential for weather forecasting and climate research. This study presents a high-accuracy precipitable water vapor (PWV) dataset from 55 GNSS stations along China’s coast (2009–2019). PWV retrievals utilized weighted mean temperature (T_m) and zenith hydrostatic delay (ZHD) derived from fifth-generation European ReAnalysis (ERA5) products. After rigorous quality control, the dataset achieved an average completeness rate of 70 %. Validation against ERA5 PWV products showed strong agreement (mean bias: 0.80 mm; RMS error: 2.52 mm), while comparisons with radiosonde profiles yielded a mean bias of 0.90 mm and an RMS error of 3.01 mm, confirming its accuracy and reliability. Spatial analysis revealed PWV values ranging from 0 to 88.57 mm, with minima decreasing with increasing latitude and concentrated around the Yangtze River estuary. Temporal patterns exhibited prominent annual and semi-annual cycles, particularly in higher latitudes. PWV showed a strong positive correlation with sea surface temperature (SST; r = 0.76), with a 1 K SST increase leading to a 2.4 mm (7 %) PWV rise. This dataset supports high-precision applications, including PWV validation, extreme weather prediction, and climate trend analysis. The processed ZTD and PWV datasets from 55 CGN stations are accessible at https://zenodo.org/records/14639032.