Summary: | The Tibetan Plateau (TP) has been experiencing warming and wetting since the 1980s. Under such circumstances, we estimated the summer latent heat flux (<i>LE</i>) using the maximum entropy production model driven by the net radiation, surface temperature, and soil moisture of three reanalysis datasets (ERA5, JRA-55, and MERRA-2) at the Ali site over the western TP during 1980-2018. Compared with the observed <i>LE</i> of the Third Tibetan Plateau Atmospheric Scientific Experiment, the coefficient of determination, root-mean-square error, and mean bias error of the estimated summer<i> LE</i> are 0.57, 9.3 W m<sup>−2</sup>, and −2.25 W m<sup>−2</sup> during 2014-2016, respectively, which are better than those of <i>LE</i> of the reanalysis datasets. The estimated long-term summer <i>LE</i> presents a decreasing (an increasing) trend of −7.4 (1.8) W m<sup>−2 </sup>decade<sup>−1</sup> during 1980-1991 (1992-2018). The <i>LE</i> variation is closely associated with the local soil moisture influenced by precipitation, glacier, and near-surface water conditions at the Ali site. The summer soil moisture also presents a decreasing (an increasing) trend of −0.082 (0.022) decade<sup>−1</sup> during 1980-1991 (1992-2018). The normalized difference vegetation index generally shows the consistent trend with <i>LE</i> at the Ali site.
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