Spatiotemporal distribution of water vapor in the southeastern Tarim Basin

Water vapor, an important indicator for evaluating precipitation potential, plays a significant role in the scientific development of water resources in arid regions. Therefore, based on the atmospheric water vapor (GPS-PWV) records of three ground-based GPS stations in the southeastern portion of Tarim Basin between 2021 and 2024 (January to December) and hourly water vapor pressure and precipitation records from 73 ground-based meteorological observation stations across the region, an empirical calculation model (W-e) suitable for Tarim Basin local conditions was constructed. The spatiotemporal distribution of water vapor (W-PWV) content and the relationship between precipitation and duration of precipitation were determined. The results show the following: (1) The annual and seasonal high W-PWV areas are located in the plain regions, followed by the desert regions, with the mountainous regions having the lowest W-PWV. (2) For the mountainous regions, W-PWV increases in autumn across all altitudes and decreases in spring below 3000 m and in summer above 3000 m. (3) South of 38.5°N and above 1500 m, the W-PWV variation rate is low and the precipitation conversion rate is high 6 hours before precipitation. (4) For different durations of precipitation, the peak W-PWV in the study area and the mountainous regions were observed 2-3 hours before precipitation. In the plain regions, the peak W-PWV occurs earlier with increasing duration of precipitation, whereas in the desert areas, it occurs later with increasing duration of precipitation.