Estimating water balance in a Brazilian semiarid watershed using different spatial data

This study advances water balance (WB) estimation in the Paraguaçu River watershed, Brazil, by leveraging spatial data to mitigate the challenges of sparse monitoring, particularly in the semiarid region. By combining precipitation (PPT) and actual evapotranspiration (ETR) data from diverse methodologies, including IMERG, TMPA, TerraClimate (TC), and IDW interpolation, alongside ETR sources like MOD16, GLEAM, and TerraClimate, we aim to capture the watershed's physical and climatic nuances. The analysis reveals that TerraClimate data (PPTTC and ETRTC) most accurately reflect spatial variations, effectively capturing orographic effects and the semiarid climate, thus emerging as the optimal combination for depicting WB (WBTC_TC). Key findings highlight the variable precision of PPT and ETR data sources in characterizing spatial distribution and magnitude across the watershed, with TerraClimate data showing superior sensitivity to regional disparities. This sensitivity is crucial for accurately modeling the hydrological dynamics in regions with contrasting climatic conditions, from humid orographic areas to the semiarid zones. Moreover, the study underscores the importance of data validation and careful integration of spatial data, particularly in under-monitored or climatically extreme regions, to enhance the reliability of hydrological analyses. The successful integration of spatial data underscores its value in remote or data-scarce regions, reinforcing the necessity for rigorous spatial and temporal validation. This approach not only improves water management strategies but also enriches the integration with climatic and hydrological models, offering a comprehensive toolkit for addressing the complexities of watershed management in the face of climate variability. [Display omitted] •Water balance closure achieved only for variables from the same database.•Measured data combined with spatial data (WBIDW_TC) produced consistent results.•Combining multiple sources of PPT and ETR affects the accuracy of water balance.•Data validation is crucial in regions with data scarcity or extreme climates.•The MOD16 product overestimated ETR values in dry regions.