Abstract:Based on the autumn precipitation data of 301 meteorological stations in West China from 1962 to 2018 and 130 climatic system indices compiled by the National Climate Center, the autumn rainfall prediction model in West China is established by using the interannual incremental method. Four influencing factors closely related to the first three main modes of the annual increment of Huaxi autumn rainfall are selected through correlation analysis. The multivariate linear regression method is used to establish the model, and the fitting and the hindcast periods are selected as 1962-1991 and 1992-2018, respectively. The mainmode prediction model of interannual increment of Huaxi autumn rainfall has passed the significance test of 〖WTBX〗α〖WTBZ〗=0.01, which shows that the model has a high capability of fitting and forecasting. The interannual incremental forecasting models of Huaxi autumn rainfall for 301 meteorological stations are established with the same forecasting factors, and most of the models have passed the significance test. The results are checked by two indicators: symbol consistency rate and PS score. The results show that the average annual PS score is 74.5 in the hindcast test period. In terms of spatial distribution, the PS scores of all stations in the hindcast test period exceeds 60, and more than 80 points are scored in the southern of Sichuan Basin, Eastern Guizhou and Western Hunan. Compared with the PS scores of autumn precipitation forecast published by the western provinces and the National Climate Center in recent 6 years, it is found that the results of the model have significant advantages. Generally, the Huaxi autumn rain prediction model based on the interannual increment method has high prediction skills and practical application value.