Banca de QUALIFICAÇÃO: FLAVIA FERREIRA BATISTA

ANALYSIS OF PRECIPITATION EVENTS BASED ON SATELLITE DATA OVER THE PARNAÍBA RIVER WATER BASIN

Performance evaluation; Parnaíba Basin; Bias correction; Precipitation extremes; IMERG.

Satellite products, such as the Global Precipitation Measurement (GPM) Integrate Multi-Satellite Retrievals of (IMERG), present themselves as a promising tool for analyzing precipitation distribution, especially in regions with a low density of rain gauges, as is the case in Brazil. However, it is essential for end users and developers to validate and correct satellite estimates at a regional level. In this case, it is important to validate IMERG for the Parnaíba Hydrographic Basin, located in the Northeast of Brazil, as it is a basin with high water potential, and which has in part of its territory one of the largest expanding agricultural frontiers in the world. world. Therefore, the objective of this work is the evaluation and correction of precipitation estimates generated by the IMERG Early, Late and Final products in comparison with data observed on a daily scale, by rain gauges in the basin region, as well as analyzing extreme precipitation indices and comparing the performance of IMERG products after correction. Two databases will be used: one with information from rainfall stations and the other with daily precipitation estimates from the IMERG satellite, covering the period from January 2001 to December 2020. To carry out all stages of the study, a pixel-based approach will be used. point by point, selecting the grid point closest to the geographic location of the rain gauges. The efficiency of the precipitation estimates of the products was carried out using statistics such as bias, mean squared error and root mean squared error, probability of detection (POD) and probability of failure (FAR), along with the Kling-Gupta efficiency index ( KGE). To improve IMERG estimates in the studied region, the non-parametric Quantile Mapping (MQ) technique will be applied. This technique allows corrections based on probability distribution functions without parametric assumptions. Preliminary results show that IMERG Final estimates show better agreement with in situ data on a daily scale when compared to IMERG Early and Late estimates, with a visible improvement in efficiency in increasing product latency. The products showed different capabilities in observing extreme rainfall in the basin, IMERG Final presented satisfactory results indicating that it can be used as a source of data in the analysis of rainfall extremes in the basin.