Climatic characteristics of Tibetan Plateau vortex precipitation based on observations

Tibetan Plateau vortices (TPVs) are important rainfall producers generated over the Tibetan Plateau (TP), which can move off the TP under certain conditions. The TPVs greatly affect both local and downstream rainfall, but the characteristics of TPV precipitation are not yet fully understood. Accordingly, the climatic characteristics of TPV precipitation during May-August of 1998-2018 are explored in this work from multiple aspects, based on observational TPV and precipitation data sets. Generally, maximums of precipitation amount are observed over the eastern TP and in Sichuan Basin, and the TPVs contribute more than 40% of the precipitation in certain areas within the TP. For the TPVs located over the TP, the precipitation is distributed zonally with a relatively small intensity; for the TPVs beyond the TP, the associated precipitation is distributed in the southwest-northeast direction with a larger intensity. TPVs tend to be responsible for intense rainfall, that is, heavy and torrential rainfalls, and are suggested to be the major intense rainfall producers at certain stations over and downstream from the TP. Meanwhile, TPV precipitation exhibit distinctive features in separate month, for example, TPV precipitation account for the largest percentage of the total precipitation in June and the smallest in August; more than half, even 75% of the torrential rain days downstream from the TP in Sichuan Basin and the regions around 35 degrees N in central and eastern China in May, and in the regions over the TP and its eastern flank in June, July and August are attributed to TPVs.