Rainfall Erosivity Estimation Using Daily Rainfall Amounts

Rainfall erosivity shows the potential ability of the soil loss caused by rainfall and it is very important for predicting soil loss quantitatively. A rainfall erosivity model using daily rainfall amounts to estimate half-month rainfall erosivity directly was established from data of 71 weather stations in China. The average coefficient of determination for all stations was 0. 718 and the average relative error estimating the annual average rainfall erosivity was 4.2% . Both parameters of α and β in the model were different in different regions. The parameter a was high correlative with parameter β and parameter β was related to rainfall characteristics, so both parameters could be estimated by using rainfall indexes. With the set of parameter values estimated by using rainfall indexs, the average coefficient of determination decreased to 0. 697 and the average relative error estimating the annual average rainfall erosivity increased to 17. 3% . The model worked very well in the regions where the rainfall was abundant and the result was on the low side when extreme storm erosivty was estimated. The daily rainfall erosivity model could be used to estimate the annual average rainfall erosivity and its seasonal distribution.