Evaluation of the integration between short-term atmospheric and hydrological forecasts for the State of Minas Gerais

Minas Gerais plays a major role in Brazil’s water resources, but its extensive river system also contributes to the occurrence of floods. Although there are specialized centers for issuing hydrological forecasts and alerts, these efforts are still concentrated in priority areas and do not cover the entire state. In this context, the objective of this study was to enhance the capacity for flow forecasting by integrating the Eta atmospheric model with the MGB-IPH hydrological model, applied to the main river basins of Minas Gerais. To this end, daily precipitation forecasts with a lead time of up to eight days, produced by the Eta regional atmospheric model operated by CPTEC/INPE, were used for the period from 2001 to 2024. These forecasts were employed as input data for the MGB-IPH distributed hydrological model to generate daily discharge forecasts up to eight days in advance. The accuracy of the forecasts was assessed through visual analyses and the statistical indicator Mean Relative Error (MRE). The results demonstrated that the Eta/MGB system was able to represent the observed discharge values and can be useful in supporting water resource management in the main basins of Minas Gerais. However, limitations related to the quality of hydrological data and uncertainties associated with precipitation estimates and forecasts still compromise part of the forecasts’ accuracy. Therefore, it is recommended that future studies incorporate precipitation correction techniques, more comprehensive statistical analyses, and comparisons between different atmospheric models, with the aim of improving the forecasting system’s performance.