Impacto sobre a modelagem hidrológica na bacia do rio Piancó-PB com a utilização de dados de índice de área foliar e albedo provenientes do sensor orbital MODIS

Abstract

The good water resources management is key point for the economic, social and environmental development of any society. Bringing this context to the Brazilian northeastern semi-arid region it becomes more evident, considering the low rainfall rates and the secular disregard of the Brazilian government for this region, added to the susceptibility of this region to great periods of drought. Hydrological modeling appears as a useful tool to assist in water resources management, but due to lack of infrastructure in many Brazilian watersheds, including the Piancó river basin located at Paraiba state river, meteorological and field variables cannot be measured, forcing researchers to go back Of literature data and / or similar regions to continue their work. Tabulated data do not represent the interannual variability and decrease the distributed physical characterization, the main point of distributed hydrological models. With this scenario described above the objective of this work was to use albedo and leaf area index (LAI) data derived from the MODIS sensor, replacing the fixed values tabled in order to increase the space-time variability of the model and to verify the impacts on the intermediate hydrological processes (Evapotranspiration and soil moisture), impacts on peak flows, cumulative flows from year to year and variation of monthly averages for basin specific cells. The results showed little reduction in real total ET values and subtle increase in soil moisture values. There were no significant impacts on the hydrological processes analyzed in the basin. Intermediate processes within the cells total ET and soil moisture values varied between ± 5% for the two variables. In relation to the total flow values, there was a reduction of the peak flows in 6 of the 11 analyzed years, however these reductions were not significant being around 1% and when overestimated the values ranged from 3% to 8% when compared to the round pattern. An underestimation of the albedo values for hydrological response units 4, 5 and 6 was observed. As averages, where they did not show significant values, they were also between ± 5% for both total real ET and soil moisture. A 6 month lag was observed throughout the albedo data series in relation to the tabulated data indicating a different dynamics of this variable or error in the image acquisition by sensor.