Spatial and temporal assessment of the extreme and daily precipitation of the Tropical Rainfall Measuring Mission satellite in Northeast Brazil

Abstract

ABSTRACT This study assesses the ability of the Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) 3B42 Version 7 (3B42 V7) product to estimate the occurrence and intensity of daily precipitation events, emphasizing extreme events, over a 16 year period (2000 to 2015) in the Northeast region of Brazil (NEB), which is characterized by different climatic conditions and high seasonal and spatial variability of rainfall. Statistical techniques such as the paired Student t-test, receiver operating characteristic curve (ROC), sensitivity analysis, cluster analysis and density graphing, along with descriptive statistics such as bias, standard deviation, mean square error and root mean square error were used. The results indicate that the quality of the satellite estimates depends on the seasonal period and the location and time scale in which the precipitation events occur. In general, the daily precipitation estimates of the satellite are statistically equal (p-value > 0.05) to those observed by rain gauges, except in the NEB east coast, where the observed precipitation values are associated with the occurrence of warm clouds. Regarding the extreme events, the satellite did not provide good estimates of extreme daily precipitation. However, rain accumulated in two days is enough to obtain better results for the quality of the extreme precipitation estimates coming from the satellite. Thus, the study provides users of the TMPA 3B42 V7 with prior knowledge regarding the quality of the estimates regarding the occurrence and intensity of precipitation events, especially extreme ones, by seasonal period in different areas of NEB.