## 4 Intercomparison of ET Estimation among the Temperature-Based Models
However, in more complex mountainous areas, both models faced challenges in capturing radiation and heat transfer on steep slopes. However, the SSEB model displayed temporal consistency [34]. In 2014, a study compared two versions of the TSEB model, TSEB-PT and TSEB-PM. The purpose was to better account for varying vapor pressure deficits in advective, semiarid climates. The comparison was conducted using measurements from irrigated cotton fields in Texas. The study found that the TSEB-PM model provided improved accuracy in estimating evaporation and transpiration compared to the TSEB-PT model. The 15-minute interval calculations showed better agreement with measurements compared to time scaling methods. The study concluded that the choice of radiometric surface temperature measurement time did not significantly affect the results [109]. In the same year, the developed model called SEB-4S represented the energy fluxes of different surface components in agricultural fields. The study tested SEB-4S against two benchmark models and found that SEB-4S provided significantly more accurate and robust estimates of evapotranspiration. The model showed potential for operational use in irrigated agricultural areas using high-resolution remote sensing data [100]. In 2015, a study proposed ETML based on a trapezoid framework. The study evaluated the model's performance using Landsat data and found that ETML accurately estimated latent heat flux compared to tower observations. The model reduced subjectivity and uncertainties compared to simpler trapezoid interpolation models. The study suggested that ETML had the potential to expand the application of trapezoid framework-based ET modeling approaches [101]. Moreover, the four commonly used models, METRIC, SEBAL, SEBS, and SSEBop, were compared for estimating ET in the Midwestern United States. The models were validated for three cropland sites, and all four models reasonably captured the variation of ET. METRIC and SSEBop performed well with low errors, while SEBAL and SEBS showed some bias in daily ET estimation. The study emphasized the strengths and limitations of these models for water resource management [110]. In a valuable work conducted by [111], SEBAL, METRIC, S-SEBI, SEBS, and SSEBop were evaluated for their accuracy in estimating ET in the humid southeastern United States. They compared the measured ET data from four sites with the predictions from the models using Landsat images from 2000 to 2010. The results revealed that SEBS performed the best overall, exhibiting the lowest root mean squared error (RMSE) of 0.74 mm/day. On the other hand, SSEBop consistently overestimated ET with an RMSE of 1.67 mm/day. The other models, SEBAL, METRIC, and S-SEBI, fell between SSEBop and SEBS in terms of performance. However, for short grass conditions, SEBAL, METRIC, and S-SEBI showed better accuracy than SEBS. In conclusion, SEBS appears to be the most suitable model for humid regions, but it may require modifications to enhance performance over short vegetation. Moving on to the study conducted by [112], three remote models were evaluated, METRIC, LST-VI triangle, and SSEB for estimating regional ET in an oasis-desert region during a growing season. The researchers assessed the models' performance by comparing them with surface flux data from five eddy covariance flux towers at a pixel level for different land-cover types. The results showed that METRIC and SSEB exhibited good correlations (R\({}^{2}\) > 0.90) with the measured latent heat flux, while the LST-VI triangle model tended to overestimate available energy. Specifically, the LST-VI triangle model had the highest consistency with METRIC in farmland with an R\({}^{2}\) of 0.98 and an RMSE of 13.69 W m\({}^{-2}\). Overall, METRIC outperformed the other models, while the LST-VI triangle model tended to overestimate and SSEB underestimated higher \(LE\) values. Sensitivity analysis revealed that the SSEB and LST-VI triangle models were more sensitive to estimated surface temperature and available energy compared to METRIC.