Grey model based flood risk years forecasting in Nanjing, China

Grey Model is a useful method for forecasting with limited data and has been widely used in a great variety of disciplines. This study gives a brief y review of the operation of grey prediction, and then use the GM(1,1) model to forecast flood year in Nanjing based on the rainfall data and the Flood index from 1951-2000. The forecasting results suggest that there could possibly be a flood year in between 2003 and 2004. Similarly, a flood year could appear in between 2022 and 2023, 2047 and 2048. The checking of the prediction precision grade is “Good”, and in fact, the year of 2003 is found to be a flood year, which implies that the forecasting result is reliable. Hence the forecasting data would be of practical importance for scientific flooding preparedness and flooding risk management.