Abstract:Based on the hourly precipitation data of 1666 stations during 2011-2015 and high-precision terrain grid data of Sichuan Basin, the relationship between the characteristics of precipitation and altitude is investigated by using statistical diagnostic methods. The main conclusions are as follows. (1) The total precipitation increases with the elevation of altitude. Total rainfall day, light and moderate rain days also show the same trend. However, the total precipitation is not the same as that of the rainy day. The preci-pitation growth area is mainly concentrated in the altitudes 200-1200 m. When the altitude exceeds 1200 m, precipitation decreases rapidly. Heavy rainy days and rainstorm days are also rapidly decreasing after an altitude of more than 1200 m. (2) The heavy rainfall along the mountains of the northwest and southwest of the basin mainly results from the strong hourly rainfall. But the heavy rainfall in the notheast of the basin is mainly caused by the persistent precipitation. (3) The complex topography of Sichuan Basin has a significant effect on the diurnal variation of precipitation. The appearance of peak frequency in one day is ahead of time with the elevation of altitude. And the first occurrence time of severe short-time heavy rainfall postpones with the elevation of altitude.