Research progress of precipitation process in the water vapor channel of Yarlung Zsangbo Grand Canyon, China

The Yarlung Zsangbo Grand Canyon (YGC) acts as a critical water vapor channel for the Tibetan Plateau, profoundly influencing regional and downstream hydrometeorology. Significant research progress has recently been made in understanding the complex precipitation processes within this unique corridor, integrating multi-source observations, satellite retrieval evaluation, and model simulations.

A core finding is the systematic underestimation of precipitation over the eastern Himalayas by widely used products like GPM IMERG, which has been quantitatively reduced through improved algorithms informed by dense in-situ gauge data. Comprehensive investigations utilizing a novel multi-platform observational network have elucidated the complete three-dimensional structure and life cycle of precipitation systems within the YGC. This network, combining ground-based radars, disdrometers, and radiosondes, has revealed distinct seasonal shifts in precipitation microphysics. Notably, mixed-phase and ice-phase processes play a key role in these seasonal transitions, with significant differences identified between the southeastern Tibetan Plateau and lower-altitude regions. Furthermore, two dominant types of heavy precipitation events have been classified and their distinct dynamic and thermodynamic mechanisms have been established.

Research also highlights the challenges of reanalysis accuracy in complex terrain, while providing pathways for improvement. Leveraging these mechanistic insights, recent efforts have successfully improved the forecasting of heavy precipitation in the YGC through optimized model physics, specifically by integrating enhanced cumulus and turbulent orographic form drag (TOFD) parameterization schemes. Collectively, these studies advance the quantitative understanding of precipitation processes in this major water vapor channel, offering crucial insights for hydrological modeling, climate studies, and numerical weather prediction in high-altitude complex terrain.