Applicability of satellite rainfall estimates for erosion studies in small offshore areas: A case study in Cape Verde Islands

To assess the usability of satellite rainfall estimates for erosion studies in Cape Verde, the 3B42 and 3B43 products from TRMM, and the Multi-Sensor Precipitation Estimate MPE from Meteosat are compared to daily and monthly ground rainfall measured between 1998 and 2010. TRMM estimates from 1998 and MPE from 2009 were studied and it was found that they detect the general trend and direction of rainy clouds but underestimate the amount of rainfall compared to rain gauges. To obtain an improved rainfall estimate from Meteosat data, the cloud top temperature derived from the 10.8 μm infrared channel was correlated to rainfall intensity measured at a 3-minute interval between 2008 and 2010 by a Parsivel optical disdrometer. A modified exponential equation of daily rainfall intensity as a function of cloud top temperature was obtained. The equation was applied to 15-minute intervals from the infrared channel to obtain 15‐minute rainfall and summed up as daily rainfall. The daily rainfall depths estimated from cloud top temperature showed a better correspondence with the amounts measured by ground gauges on the island (r = 0.75), and are a first approach to cope with lack of short duration rainfall data for erosion studies in island states such as Cape Verde.