ANÁLISE DE SÉRIES HISTÓRICAS DE PRECIPITAÇÃO PLUVIOMÉTRICA PARA O MUNICÍPIO DE RIO VERDE – GO E ENTORNO

Abstract

This work analyzes historical precipitation time series in Rio Verde municipality, Goiás, and its surrounding area, covering the period from 1974 to 2024, aiming to characterize the temporal and spatial behavior of rainfall and its applicable information for this locality of strong agricultural and livestock vocation and as a basis for future environmental studies. Daily data from 11 rainfall stations of the National Water Agency (ANA) and one meteorological station of INMET were used, obtained from HidroWeb and BDMEP systems, comprising five decades of records for each measurement post. Data gaps were filled using Simple Linear Regression between hydrologically similar stations, and the consistency of these correlations was evaluated using the Double Mass method. Subsequently, descriptive statistical calculations were performed (means, range, standard deviation, and coefficient of variation) for key precipitation variables: maximum daily annual, wet and dry periods, and total annual. The mean spatial precipitation from ten stations was 1398.97 millimeters annually, with 91.49% concentrated in the rainy season (October-April) and only 8.51% in the dry season (May-September). Spatial distribution of means was performed in a Geographic Information System environment, with interpolation using Inverse Distance Squared (IDS) in QGIS 3.40.11 software, generating isohyetal maps at one-kilometer resolution, and temporal variability observed in scatter plots. For trend analysis, the non-parametric Mann-Kendall test with Sen's Slope robust estimator was applied, revealing statistically significant decreasing trends at the 5% level for mean variables of the dry period (p=0.003; reduction of 1.78 millimeters per year) and total annual (p=0.005; reduction of 3.78 millimeters per year). Final results identified seasonal concentration of rainfall due to interannual variability intensifying the dry season and progressive reduction in total annual precipitation. This information serves for water resources management and agricultural activities in Rio Verde municipality and surrounding area.