Synergistic Effects of Bay of Bengal Tropical Cyclones and Tibetan Plateau Vortices on Water Vapor Transport over the Tibetan Plateau in Early Summer

The Bay of Bengal (BoB) tropical cyclones (TCs) and the Tibetan Plateau vortices (TPVs) are two crucial weather systems influencing the Tibetan Plateau (TP). Their synergistic effects can lead to widespread heavy precipitation events on the TP. In this study, we employ the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model to track the trajectory of water vapor transport during three large-scale precipitation events on the TP under the combined influence of BoB TCs and TPVs. The results indicate that low-level water vapor from the BoB under the influence of BoB TCs was cyclonically entangled into the cyclonic circulation, lifted and transported northward by southwesterly flow to the southeastern part of the TP, which contributes to the moistening of the entire troposphere there. Additionally, convergence of the cyclonic circulation of the TPVs on the northern TP further transports water vapor collected in the southeastern TP northward, conducive to the maintenance and development of precipitation systems, thus inducing widespread heavy precipitation events over the TP.