Climatology and Interannual Variability of the Western Tibetan Plateau Precipitation and its Moisture Sources in Boreal Winter

The western Tibetan Plateau (TP) is the hydrologic source over the TP in cold season. In this study, the climatology and interannual variability of the precipitation over the western TP in boreal winter are explored. The moisture origins and paths are detected using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model. Analysis of specific humidity along the backward trajectories is used to reveal the sources of moisture and their contributions to the moisture supply over the WTP. In climatology, the precipitation is generated as a result of upward air motions on the windward side of WTP. Under the influence of the mid-latitude westerly and subtropical high over the Arabian Peninsula, three key moisture sources are identified, i.e., the central and north Atlantic, central Eurasian-north Africa, and the Arabian Sea-Arabian Peninsula-north Indian ocean. The WTP precipitation variation are found to be closely associated with the El Niño-Southern Oscillation (ENSO) as well as a cyclone of mid-latitude teleconnection in the subtropical jet.