Abstract: Kashi river basin, the west part of Tianshan Mountain, was chosen for this study. Based on the data of hydro-meteorological station from 1990 to 2000, telemetry station in 2005 and CFSR station from 1990 to 2000 and 2005, three correction methods were used to correct the precipitation of CFSR stations: the ratio between the mean monthly precipitation of Jilintai station and the mean monthly precipitation of No.11 CFSR station from 1990 to 2000 was the first method to correct the CFSR precipitation data; the ratio between the amount of telemetry precipitation and the amount of CFSR precipitation in 2005 at each CFSR station was the second method; the correlation between No.10 CFSR station and each CFSR station and the precipitation data of Wulasitai station was the third method. Then the effects of runoff simulation were analyzed based on the VIC model. After the analyzing of time series of precipitation, the features of CFSR precipitation in time scale and spatial scale are same to the features of real precipitation. The results of runoff simulation showed that, (1) different methods to correct CFSR precipitation have obviously different effects on runoff simulation. (2) Compared with other methods to correct CFSR precipitation, the way which used the correlation between No.10 CFSR station and each CFSR station and the precipitation data of Wulasitai station is the best one among other methods from the effects of runoff simulation. The efficiency coefficients of this model based on the best correction method in the calibration and verification period are both above 0.80, the relative errors of runoff are both under 15.0%. The best correction method in this study takes two factors - the change of precipitation in time scale and spatial scale - into consideration, and it has a better application in the numerical simulation of runoff than other methods, especially in scare data area.

Key words: CFSR precipitation data, Precipitation correction method, VIC model, Scarce data area