Publications

Ghafourian, S; Aminnejad, B; Ebrahimi, H (2023). Evaluating Direct Assimilation of Satellite-Based Potential Evapotranspiration into SWAT for Improving Hydrological Modeling. JOURNAL OF HYDROLOGIC ENGINEERING, 28(11), 5023019.

Abstract
A correct estimation of evapotranspiration (ET) is required to determine the amount of available water in any watershed. Potential evapotranspiration (PET) is used to estimate actual evapotranspiration (AET). The Soil and Water Assessment Tool (SWAT) has different methods to compute PET; in data-scarce watersheds hydrological modeling is typically challenging. Although there are a lot of remotely sensed PET (RS-PET) data, validation of hydrological models using these data has rarely been studied in such watersheds. Thus, the purpose of this paper is to assess the impacts of direct assimilation of RS-PET on water balance components using SWAT for a basin in Iran with limited data. To this end, we changed the SWAT source code to automatically integrate RS-PET data. The performance of the model was then evaluated using streamflow data and AET for the period 2001-2005. The results reveal that the Default PET model overestimates soil moisture, underestimates AET, and ultimately fails to appropriately capture streamflow at the watershed's outlet. However, by incorporating RS-PET, the model improves the accuracy of PET, AET, soil moisture, and streamflow. For example, in the Default PET scenario, the Nash-Sutcliffe efficiency streamflow was 0.66, whereas it was 15% higher in the RS-PET scheme. The findings also demonstrate the SWAT parameters' sensitivity to PET values and the efficiency of RS-PET in enhancing hydrologic modeling in regions with limited data.

DOI:
10.1061/JHYEFF.HEENG-5936

ISSN:
1943-5584