1 INTRODUCTION Water vapor transport, as an important component of the global water cycle, is the major way of transferring ocean water to land. The studies of water vapor transport mainly include the water vapor content, transport paths and water vapor sources (Li et al., 2018). The related studies are favorable for a deeper understanding of the basin water cycle and water resource characteristics, as well as the macrocontrol of water resources (Oki & Kanae, 2016).