A Step towards incorporating return period in rainfall erosivity of India using high temporal resolution Satellite precipitation product

Abstract

Abstract Return period analysis has been incorporated into the Rainfall erosivity of India. This has been performed by applying frequency analysis on the annual rainfall erosivity factor data series with the help of twelve widely used theoretical probability distributions. The annual rainfall erosivity factor was calculated using IMERG half-hourly satellite precipitation product and with the standard method given in the Revised Universal Soil Loss Equation (RUSLE) handbook. The spatially distributed map of best-fitted distribution was generated. Return level values of 2, 5, 10, 25, 50 and 100-year return periods are evaluated using the cumulative distribution function of best fitted distribution and a spatially distributed map of each return period was prepared. These maps will offer liberty to the stakeholders and policymakers to decide on the level of risk they are willing to take. Moreover, the high spatial resolution gridded data will minimise the probable error of interpolated maps in areas with a limited number of stations or no stations. In traditional practice, the average annual rainfall erosivity is considered for computing soil loss. However, this study revealed that the average annual rainfall erosivity fell between return levels of 2 and 5-year return periods in around 94% of the studied area, highlighting the underestimation of rainfall erosivity.