Spatial Analysis of Precipitation Variability in Parnaíba River Watershed, Northeast of Brazil

Abstract

The occurrence of precipitation in northeastern Brazil results from the meteorological action of systems that act at local, regional and global scales. Oscillations in the physical mechanisms that control these systems produce variations in spatial and temporal distribution of rainfall, resulting in years with scarcity, excess or normal rainfall conditions. Understanding the rainfall dynamics is extremely important for proposing strategies to face extreme events such as droughts and floods. Therefore, this work aimed to present a spatial analysis of rainfall variability in the Parnaíba river watershed (BHRP), located in the northeast of Brazil. For this purpose, precipitation data estimated by multiple atmospheric monitoring satellites (TRMM Multi-Satellite Precipitation Analysis - TMPA) were used, with 0.25º x 0.25° of spatial resolution , for a period of 22 years (1998-2019). Statistics were calculated to obtain extreme conditions, averages and rainfall variations. The Quantile technique was used to identify the standard years for each cell in watershed grid. The use of rainfall data estimated by remote sensing made it possible to understand the spatial distribution and variation of rainfall along the BHRP. Extreme drought periods were observed in different regions in the years 1998, 2007, 2012, 2015 and 2016, while the years 2000, 2008, 2009 and 2011 were extremely rainy. No spatial pattern of precipitation condition distribution can be identified along the time series, which reinforces the need to establish continuous monitoring of BHRP precipitation, aiming to subsidize programs to face extreme events, and water resources management actions.