## 4 Discussion  
The evaluation of DisALEXI-PT and DisALEXI-PM indicates little difference in the magnitude and accuracy of their daily total ET estimates when compared to observations at vineyard and orchard sites. However, the evaluation of contributions from individual fluxes E and T for DisALEXI-PT and DisALEXI-PM show considerable differences, both in comparison to CEC-derived fluxes and to one another. As the name of each implies, DisALEXI-PT and DisALEXI-PM differ in the initial and subsequently iteratively adjusted derivation of T\({}_{\mathrm{c}}\), with DisALEXI-PT using a modified Priestley-Taylor approach and DisALEXI-PM using the Penman-Monteith. Such a difference allows VPD, and potential advective conditions, to be explicitly accounted for in the DisALEXI-PM approach (omitted in DisALEXI-PT). Aligning with past studies [38; 40; 43], DisALEXI-PM performs best under advective conditions (sites RIP and VAC) when analyzing partitioned E and T estimates. However, regardless of differences in E and T, summation equates to analogous DisALEXI-PT and DisALEXI-PM total ET estimates, suggesting advective conditions only affect partitioned estimates and not total ET within the proposed modeling frameworks. Improvements in DisALEXI-PM-derived E and T can be attained by utilizing more site-specific r\({}_{\mathrm{c}}\) values rather than holding the r\({}_{\mathrm{c}}\) constant at 50 s m\({}^{-1}\). These results align with [43], where TSEB based on the Penman-Monteith formulation overestimated T, but TSEB based on utilizing a site-specific r\({}_{\mathrm{c}}\) value improved T estimates. Work is underway to address this limitation within the DisALEXI-PM approach by implementing the results of [43] within the DisALEXI framework, including the transition of site-specific, empirically driven relationships into more physically based relationships that can be applied at scale, similar to [77]. Under drought conditions and the threat of continued water restrictions for agricultural irrigation in the state of California, many parcels of land are being fallowed, creating more instances of irrigated cropland adjacent to dry barren parcels of land. Such a situation is likely to lead to increased horizontal advection of hot/dry air across irrigated fields, increasing the evaporative demand and causing latent heat fluxes to exceed available energy over irrigated fields. Therefore, careful consideration should be taken when validating satellite-based ET models over California. An example of such an instance was shown at site RIP, where advective conditions caused large differences between the closed and unclosed observed ET. A comparison of the DisALEXI-PT- and DisALEXI-PM-derived ET to the observed ET at RIP showed a strong negative bias to the energy-balanced closed ET estimates for high ET values (ET \(\geq\) 4 mm day\({}^{-4}\)), whereas the biases improved greatly when compared to the unclosed estimates for the same time period. DisALEXI-PT and DisALEXI-PM similarly adjust T\({}_{\mathrm{a}}\) until the aggregated ET converges with the ALEXI ET. However, given differences in the derivation of T\({}_{\mathrm{c}}\), these T\({}_{\mathrm{a}}\) adjustments  
Figure 11: Spatial maps of LAI, LST, and the differences between DisALEXI-PT and DisALEXI-PM (in mm day\({}^{-1}\)) for E, T, and ET for all sites on Landsat-8 overpass dates during June 2021 (specific dates listed in text). The black dot indicates flux tower location. will affect T\({}_{\rm c}\) and T\({}_{\rm s}\), and by association, T and E differently. The results suggest that the DisALEXI-PM ET values converge on the ALEXI ET with more proportionate adjustments to E and T, whereas the DisALEXI-PT convergence is primarily met with adjustments to E, the exception being when soil evaporation is \(\leq\) 0 and the Priestley-Taylor term (\(\alpha\)) is allowed to change from its initially assigned value (Equation (4)). Therefore, conditions leading to large differences between the ALEXI ET and the initial aggregated ET can have large ramifications.