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<p>State-of-the-art evaporation models usually assume net radiation (<span class="inline-formula"><i>R</i>_n</span>) and surface temperature (<span class="inline-formula"><i>T</i>_s</span>; or near-surface air temperature) to be independent forcings on evaporation. However, <span class="inline-formula"><i>R</i>_n</span> depends directly on <span class="inline-formula"><i>T</i>_s</span> via outgoing longwave radiation, and this creates a physical coupling between <span class="inline-formula"><i>R</i>_n</span> and <span class="inline-formula"><i>T</i>_s</span> that extends to evaporation. In this study, we test a maximum evaporation theory originally developed for the global ocean over saturated land surfaces, which explicitly acknowledges the interactions between radiation, <span class="inline-formula"><i>T</i>_s</span>, and evaporation. Similar to the ocean surface, we find that a maximum evaporation (<span class="inline-formula"><i>L</i><i>E</i>_max</span>) emerges over saturated land that represents a generic trade-off between a lower <span class="inline-formula"><i>R</i>_n</span> and a higher evaporation fraction as <span class="inline-formula"><i>T</i>_s</span> increases. Compared with flux site observations at the daily scale, we show that <span class="inline-formula"><i>L</i><i>E</i>_max</span> corresponds well to observed evaporation under non-water-limited conditions and that the <span class="inline-formula"><i>T</i>_s</span> value at which <span class="inline-formula"><i>L</i><i>E</i>_max</span> occurs also corresponds with the observed <span class="inline-formula"><i>T</i>_s</span>. Our results suggest that saturated land surfaces behave essentially the same as ocean surfaces at timescales longer than a day and further imply that the maximum evaporation concept is a natural attribute of saturated land surfaces, which can be the basis of a new approach to estimating evaporation.</p>