As chuvas na região de planejamento Sudoeste de Mato Grosso: interrelações entre padrões, variabilidades, tendências e ritmos

Abstract

Understanding patterns, variability, and trends in precipitation is essential for interpreting climatic dynamics in regions where changes in rainfall regimes impact socioeconomic and environmental dimensions. In the Southwest Planning Region of Mato Grosso (RPSMT), which encompasses Cerrado, Amazonian Transition Forest, and Pantanal, rainfall reflects the operation of atmospheric systems and contemporary processes linked to environmental transformations and land use. The hypothesis posited was one of climatic disarticulation of the regional pluviometric regime, indicated by greater interannual irregularity, intensification of prolonged droughts, and increased extreme events. The general objective was to analyse the spatiotemporal variability of precipitation in the RPSMT, identifying patterns, trends, and their relationships with the atmospheric systems that structure climatic rhythm. Interannual variability was evaluated between 2000 and 2022, whilst trends and extremes were analysed from 1980 to 2022. Climatic rhythm was examined through daily precipitation from two meteorological stations across three standard years (2011, 2014, and 2020), representative of habitual, wet, and dry conditions, considering the operation and participation of mEc, ZCAS, mTc, mP, and mTa. The research was anchored in Geographic Climatology, integrating statistical, geostatistical, and rhythmic analyses, with data from 42 ANA rainfall stations and two Inmet meteorological stations, processed in Excel, R language, Past, and Jamovi. Gaps were filled using Regional Weighting and validated by Double Mass (r² > 0.996). Descriptive statistics, Shapiro-Wilk, Mann-Kendall, Pettitt, and Kruskal-Wallis tests were applied, alongside Spearman correlation and standard year definition by quantiles. The series were grouped into three homogeneous areas through multivariate analysis, and spatial patterns were mapped using IDW and Ordinary Kriging. Extreme indices (ETCCDMI/WMO) were calculated with RClimDex. Precipitation genesis was identified through rhythmic analysis with daily data, synoptic charts, and MODIS/GOES imagery. Results evidenced strong seasonality and spatial heterogeneity. Between 2000 and 2022, the annual average was 1,425 mm, with 83% of rainfall concentrated between November and April, and a latitudinal gradient with maxima in the Amazon-Cerrado transition (1,995 mm) and minima in the Pantanal area (1,148 mm). Interannual variability was moderate (CV = 29%), with 56% habitual years, 22% wet years (2014, 1,775 mm), and 22% dry years (2020, 1,058 mm). From 1980 to 2022, an increase in consecutive dry days (CDD) and daily intensity (SDII) was observed, associated with reduced rainy days (CWD) and total precipitation (PRCPTOT), alongside homogeneity breaks between 2000 and 2007, indicating growing instability. Rhythmic analysis demonstrated that in 2011 (habitual), mEc (36%) and ZCAS (48%) alternated, accounting for approximately 80% of convective rainfall; in 2014 (wet), mEc (65%) and ZCAS (25%) intensified convection, including during winter; in 2020 (dry), suppression of mEc and greater influence of mTc (22%) and mP (18%) prolonged drought, with 128 consecutive dry days. In summary, precipitation in the RPSMT presents marked seasonality, spatial heterogeneity, and intensification of interannual variability, supporting the hypothesis of climatic disarticulation and providing inputs for territorial planning and environmental management in a climate emergency scenario.