Variability in and Formation of Homogeneous Regions of Precipitation Trends Across the Amazon River Basin, Determined From the Global Precipitation Climatology Centre - Gpcc

Abstract

Abstract Spatiotemporal patterns of precipitation are influenced by complex interactions between climate and land cover changes, such as deforestation, fires and droughts. The Amazon River Basin has local and global impacts in regard to the hydrological cycle; therefore, it is fundamental to understand how precipitation patterns and intensity are changing. The aim of this study was to analyze precipitation trends and form homogeneous regions of precipitation trends in the Amazon River Basin using data from the meteorological satellite Global Precipitation Climatology Centre (GPCC), applying nonparametric methods (Mann-Kendall, Spearman and Sen's slope) and fuzzy C-means to identify specific regions that are undergoing changes in hydrological patterns. The results show changes in the behavior of rainfall over time and in the intensity of the events. The statistics applied to form clusters resulted in 6 well-divided homogeneous groups, each with unique characteristics. Specifically, the central-southern areas of the basin showed negative precipitation trends (-1.17 mm/year) forming a homogeneous region (RH 1), while in the northern region, there was an increasing trend in precipitation (2.73 mm/year). In general, over the 37 years studied, the wet areas have tended to become wetter and the dry areas drier. Other homogeneous regions had their own results and unique characteristics, which are in agreement with other studies, such as those in Porto Velho, Rondônia, where this area had a diagonal pattern of precipitation decrease.