Análise comparativa do balanço hídrico climatológico médio e sequencial do estado do Ceará: influência dos métodos de estimativa da evapotranspiração potencial

Abstract

This study conducted a comparative analysis of the average and sequential climatological water balance in Ceará State, Brazil, evaluating the influence of Thornthwaite (1948) and Penman-Monteith FAO (1998) methods on potential evapotranspiration (ETP) estimation. Using data from 12 INMET meteorological stations (1961–2020), the research assessed methodological discrepancies in water balance components (deficit, surplus, storage), identified extreme years (1985 as the wettest and 1993 as the driest), and calculated climatic indices (hydric, aridity, and moisture). Results revealed that the Penman-Monteith FAO method consistently produced higher ETP values (e.g., +699.5 mm/year in Campos Sales) and amplified water deficits (e.g., +668.9 mm/year in Campos Sales), while Thornthwaite underestimated these parameters, particularly during dry periods. Hydric surplus was more pronounced in coastal regions (e.g., +87.8 mm in Fortaleza) but minimal in semi-arid inland areas. Sequential analysis highlighted intensified drought severity in dry years with Penman-Monteith FAO, emphasizing its sensitivity to variables like radiation and humidity. Climatic indices also varied significantly, with increased aridity (up to +14.8 in Campos Sales) and reduced moisture (e.g., -35.9 in Guaramiranga) under the FAO method. The study concludes that the Penman-Monteith FAO method provides a more accurate representation of hydroclimatic conditions, particularly in drought scenarios, and is recommended for water resource management in semi-arid regions. However, its complexity necessitates local adaptations, whereas Thornthwaite’s simplicity limits its reliability in critical contexts. These findings underscore the need for robust methodologies to address climate variability impacts in water-scarce regions.