Abstract: According to the ERA-Interim data, the 21-year water vapor transport flux and divergence over the main water-receiving area of the water diversion project in central Yunnan Province were calculated. The spatial-temporal characteristics of water vapor transport, convergence and divergence in the studied area were also analyzed. Results demonstrate that the annual average water vapor transport in the studied area gradually increases from the northwest to the southeast, and is dominated by latitudinal transport. The source of water vapor moves with the seasons and is controlled by southwest wind in summer. The intensity of water vapor transport in the studied area in summer is significantly lower than that in the other three seasons. From May to July, the intensity of water vapor transport shows a gradual decline. In July, a water vapor convergence center emerges in the south of the studied area on the 850 hPa barosphere and a water vapor divergent zone in the southwest on the 450 hPa barosphere, beneficial for the formation of precipitation in the southwest.

Key words: water vapor transport, water vapor transport flux, water vapor convergence, water vapor divergence, water diversion project in central Yunnan Province