Improving evaporation estimations over hypersaline water bodies using a factor based on total dissolved solids

• Evaluating various models for estimating evaporation from hypersaline water bodies. • Considering the effect of Total Dissolved Solids on evaporation from hypersaline bodies. • Introducing EF-TDS for estimating evaporation of hypersaline water bodies. • Applying EF-TDS to improve the accuracy and efficiency of remote sensing models. Evaporation plays a key role in the water balance of hypersaline lakes, where high Total Dissolved Solids (TDS) concentrations considerably impact evaporation rates. In this study, a novel Evaporation Factor based on TDS (EF-TDS) was introduced to improve evaporation estimates from hypersaline water bodies. Lake Urmia, one of the world’s largest hypersaline lakes, located in northwestern Iran, was selected as the case study. The Surface Energy Balance Algorithm for Land (SEBAL) and Mapping Evapotranspiration at high Resolution with Internalized Calibration (METRIC), along with the FAO56-PM, Priestley-Taylor, and Hargreaves-Samani models, were evaluated. Additionally, the Bowen-Ratio Energy Balance (BREB) and Penman Salinity models were implemented for comparison. To implement these models, satellite data, including 30 Landsat 8 Operational Land Imager (OLI) images and 76 Moderate Resolution Imaging Spectroradiometer (MODIS) images from 2013 to 2015, were processed using the Google Earth Engine (GEE) platform. In-situ measurements from a saline evaporation pan and a modified FAO56-PM model were employed to validate the results. The findings showed that, without considering TDS, all models overestimated evaporation, while METRIC outperformed other models with a Nash-Sutcliffe Efficiency (NSE) of 0.88 compared to the modified FAO56-PM model. However, after applying EF-TDS, remarkable improvements were observed across the models, with the Priestley-Taylor model achieving the highest performance (NSE = 0.90). Moreover, EF-TDS outperformed the method of reducing vapor pressure in evaporation models. This study demonstrates the importance of accounting for TDS in evaporation models, particularly for hypersaline lakes, and highlights the effectiveness of EF-TDS in improving the accuracy of evaporation estimates.