Drought forecasting based on the standardized precipitation index at different temporal scales using ARIMA models

The time series of SPI at different temporal scales are calculated from monthly precipitation data,which was collected from 36 weather stations in Guanzhong Plain and Weibei Tablelands.ARIMA models are developed to forecast and simulate SPI series.The results show that ARIMA models can predict SPI 3,6,9 series with 1-month lead-time at the precision of under 10%,and can predict the SPI 12,24 series with 9-month lead-time at the average precision of under 10%. Forecasting precision increases with the increase of temporal scales.