Análise da relação entre evapotranspiração potencial e precipitação e do seu impacto nas vazões simuladas pelo modelo smap no estado do Ceará

Abstract

The objective of the present work is to analyze a possible relationship between monthly precipitation and potential evapotranspiration (ETo) in the vicinity of Iguatu (Ceará) and from it generate ETo series by filling the gaps with regressions between these two variables, calibrate and simulate flows with SMAP model and observe if possible alterations found in ETo impacts in the simulated flows. It was observed an higher negative correlation in the first semester, up to 70% for january, february and april, compared to the second, between 39% and 56%. It was detected a possible increase tendency of ETo along time, with predominating higher values in the last years, and a high variation between it values, up to 37% higher than mean and 26% below. The SMAP model calibrated and simulated with filled series did not result in significantly different flow values, the NASH-Sutcliffe efficiency coefficient varied between 0,84 and 0,86, except when minimum monthly values were adopted, which resulted in an significantly lower value (0,46). The results indicates that months with lower precipitation can result in higher values of ETo.