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Universidade Federal do Rio Grande do Norte (UFRN) 2022

Impactos da mudança na temperatura e precipitação sobre a resposta hidrológica de uma bacia do semiárido

Sousa, Denner Santiago de

Titre : Impactos da mudança na temperatura e precipitação sobre a resposta hidrológica de uma bacia do semiárido

Auteur : Sousa, Denner Santiago de

Université de soutenance : Universidade Federal do Rio Grande do Norte (UFRN)

Grade : Engenheira Ambiental. 2022

Résumé
Climate change will modify temperature and precipitation patterns, which are the main driving forces of concentrated hydrological models, essential tools in assessing the effects of climate change on hydrological processes. The variability of precipitation and temperature produces different responses in the streamflow simulation depending on the model and basin characteristics. These future scenarios of increased evapotranspiration, even with uncertainty about rainfall variability, may result in reduced water availability in the semiarid region. The Brazilian semiarid region has specific characteristics that have a negative impact on water availability : intense concentrated rainfall, high spatio-temporal variation of precipitation, lengthy dry period, low, high potential evapotranspiration, shallow and poorly structured soils and the occurrence of intermittent rivers. Due to the natural water deficit and the low supply of water, since the beginning of the 19th century, the construction of reservoirs has been the most used strategy in the Brazilian semiarid region to regulate flows. Thus, the work aims to evaluate how the change in precipitation and temperature impact the streamflow generation in a hydrographic basin in the Brazilian semi-arid region, the Marechal Dutra reservoir basin. Sensitivity analysis were performed in the hydrological model Soil Moisture Accounting Procedure (SMAP), which was forced from 36 stochastic scenarios where precipitation varied from 94% to 103% of its climatology together/or not with a temperature increase of 0.5°C to 4°C. In the sensitivity tests, it was observed that the average streamflow in the basin can vary from -31.36% to 10.74%. When changes in precipitation and temperature occur separately, the average flow reduces by 1.78% for each 0.5°C increase and varies by an average of 10.12% for each 3% change in average precipitation. In combined scenarios, the resulting cross effect attenuates or enhances the flow reduction. The effect of precipitation and temperature changes on drought was evaluated by the Streamflow Drought Index (SDI) which indicated the variation of non-dry periods from -31.74% to 7.19% and extreme drought from -3.39% to 13.57%.

Mots Clés  : Sensibilidade ;Seca;Modelo hidrológico concentrado ;Sensitivity analysis ;Drought;Concentrated hydrological models

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Page publiée le 16 janvier 2023