Spatiotemporal distribution of precipitation microphysical characteristics over the Tianshan Mountains based on GPM/DPR observations

Abstract

Using monthly mean Level-3 GPM/DPR products from March 2014 to February 2023, this study systematically investigates the spatial distribution, vertical structure, and microphysical characteristics of stratiform and convective precipitation over the Tianshan Mountains. The results indicate that stratiform precipitation is generally weak but widespread, with maximum precipitation rates mostly below 4 mm h⁻¹ and maximum radar reflectivity mainly ranging from 20 to 29 dBZ. Its contribution to the combined mean near-surface precipitation rate exceeds 60% annually and 90% in winter. In contrast, convective precipitation exhibits much higher intensity and pronounced extremes, with maximum precipitation rates commonly exceeding 4 mm h⁻¹ and radar reflectivity typically between 29 and 38 dBZ, locally surpassing 41 dBZ, and is primarily concentrated in summer over the western Tianshan and windward slopes. Storm-top height generally ranges from 4 to 7 km, while convective precipitation frequently exceeds 8 km, showing a clear west-to-east decreasing pattern controlled by topography. Vertically integrated liquid, ice, and total hydrometeor contents show local enhancements over the western Tianshan and windward slopes, but figure-based absolute maxima are interpreted cautiously because smoothing and panel-specific color scales can affect visual comparisons. These findings provide satellite-based evidence for improving the understanding of precipitation processes and microphysical mechanisms in complex mountainous regions.