In this paper, the atmospheric high-resolution data from the WRF model（v3.4） is used to analyze the transport and budget of water vapor, and their influences on the intensity of tropical cyclone Fitow （2013）under the condition of binary tropical cyclones have been studied. The results show that Fitow not only interacts with the surrounding environment system, but also interacts with the trailing tropical cyclone Danas（2013）, thus affecting the water vapor transport channel of Fitow. In particular, as an “collection-transfer station” for water vapor, Danas has an important impact on the strong precipitation of Fitow during its landing period.

In addition, the mesoscale water vapor budget has been analyzed. The research shows that the overall distribution evolution of the water vapor flux convergence band is consistent with the strong convection band in Fitow. It is founded that the eastern boundary is a more important source of water vapor while the western boundary serves to consume water vapor for Fitow under the condition of binary typhoons, and the vertical transport of water vapor plays an important role in the redistribution of water vapor inside the typhoon. Due to the long duration of vertical water vapor transport, it has an essensial effect on the continuous enhancement of Fitow.

This work was supported by the National Natural Science Foundation of China (41775055   41675058).