Avaliação dos dados de precipitação gerados pelos satélites GPM e TRMM

Abstract

The aim of this study is to verify the performance of the information produced by the GPM mission (Global Precipitation Measurement) and TRMM (Tropical Rainfall Measurement Mission) over the east region of São Paulo state, having ground gauges as true observations. The comparison was performed between spatially aggregated information from pluviometers and the satellites. In order to assess the quantitative rain errors, the following analyses were realized: (1) Relative Error, (2) BIAS and (3) Root Mean Square Error (RSME). For both missions, it was found that the relative differences were usually in the range of -20% to 20%; according to BIAS analyses, 68% of the satellites measurements were overestimated and the highest estimative agreement was obtained for the mesoregion of Campinas and the lowest for the Araraquara mesoregion. For the TRMM, the lowest RMSE values were found in the Araraquara mesoregion and the highest in the Piracicaba mesoregion. With the GPM satellite the closest values of rainfall were observed in the Piracicaba mesoregion, while the most distant values were identified in the Araraquara mesoregion. All analyzes made in this research demonstrated similarity between the errors generated by both satellites. Further comparative studies are necessary in order to determine possible strengths and weaknesses of each of these products.