Calculation of Rainfall Erosivity Factors in Hokkaido Using Japan Meteorological Agency Data

Abstract

The USLE-based rainfall erosivity factor was calculated from the observational data of the Japan Meteorological Agency for the whole area of Hokkaido, and its distribution was clarified. The rainfall erosivity factors were calculated by adding the thaw and snowmelt factor to the rainfall and runoff factor. The USLE method of calculating the rainfall and runoff factor uses data recorded at 10-minute intervals. Because the 10-minute-interval measurement data was shorter than that of one hour value, bias were caused in calculated rainfall and runoff factor. In this study, rainfall and runoff factor was calculated from 1-hour-interval measurement data. To convert it into the value of rainfall and runoff factor that had been calculated from the 10-minute-interval measurement data, the conversion coefficient in which the regionality was considered was multiplied by rainfall and runoff factor of 1-hour-interval measurement data.