Satellite-based estimation of rainfall erosivity for Africa

Rainfall erosivity is a measure for the erosive force of rainfall Rainfall kineticenergy determines the erosivity and is in turn greatly dependent on rainfall intensity Attempts for its large-scale mapping are rare Most are based on interpolation of erosivity values derived from rain gauge data For data-poor regions this is not an option This study examines whether erosivity can be accurately mapped for Africa using 3-hourly TRMM Multi-satellite Precipitation Analysis (TMPA) precipitation data Using intensity-erosivity relationships and 11 years of TMPA data (1998-2008) we calculated average annual erosivity We also calculated erosivity from the monthly TMPA data product using the often-applied Fournier and modified Fournier indices From literature 39 locations with long-term erosivity values were retrieved Comparison showed that the modified Fournier Index attains a much stronger correlation (r = 0 84) than the results based on 3-hourly data (r = 0 71) We conclude that (1) the 3 hourly and 0 25 degree TMPA data provide insufficient detail to represent high-intensity erosive events and (2) monthly satellite-based precipitation provides good spatial estimates of average annual erosivity (c) 2010 Elsevier B V All rights reserved