Long-term variations in actual evapotranspiration over the Tibetan Plateau
oleh: C. Han, C. Han, C. Han, Y. Ma, Y. Ma, Y. Ma, Y. Ma, B. Wang, B. Wang, L. Zhong, W. Ma, W. Ma, W. Ma, X. Chen, X. Chen, X. Chen, Z. Su
| Format: | Article |
|---|---|
| Diterbitkan: | Copernicus Publications 2021-07-01 |
Deskripsi
<p>Actual terrestrial evapotranspiration (<span class="inline-formula">ET<sub>a</sub></span>) is a key parameter controlling land–atmosphere interaction processes and water cycle. However, spatial distribution and temporal changes in <span class="inline-formula">ET<sub>a</sub></span> over the Tibetan Plateau (TP) remain very uncertain. Here we estimate the multiyear (2001–2018) monthly <span class="inline-formula">ET<sub>a</sub></span> and its spatial distribution on the TP by a combination of meteorological data and satellite products. Validation against data from six eddy-covariance monitoring sites yielded root-mean-square errors ranging from 9.3 to 14.5 mm per month and correlation coefficients exceeding 0.9. The domain mean of annual <span class="inline-formula">ET<sub>a</sub></span> on the TP decreased slightly (<span class="inline-formula">−1.45</span> mm yr<span class="inline-formula"><sup>−1</sup></span>, <span class="inline-formula"><i>p</i><0.05</span>) from 2001 to 2018. The annual <span class="inline-formula">ET<sub>a</sub></span> increased significantly at a rate of 2.62 mm yr<span class="inline-formula"><sup>−1</sup></span> (<span class="inline-formula"><i>p</i><0.05</span>) in the eastern sector of the TP (long <span class="inline-formula">>90</span><span class="inline-formula"><sup>∘</sup></span> E) but decreased significantly at a rate of <span class="inline-formula">−5.52</span> mm yr<span class="inline-formula"><sup>−1</sup></span> (<span class="inline-formula"><i>p</i><0.05</span>) in the western sector of the TP (long <span class="inline-formula"><90</span><span class="inline-formula"><sup>∘</sup></span> E). In addition, the decreases in annual <span class="inline-formula">ET<sub>a</sub></span> were pronounced in the spring and summer seasons, while almost no trends were detected in the autumn and winter seasons. The mean annual <span class="inline-formula">ET<sub>a</sub></span> during 2001–2018 and over the whole TP was <span class="inline-formula">496±23</span> mm. Thus, the total evapotranspiration from the terrestrial surface of the TP was <span class="inline-formula">1238.3±57.6</span> km<span class="inline-formula"><sup>3</sup></span> yr<span class="inline-formula"><sup>−1</sup></span>. The estimated <span class="inline-formula">ET<sub>a</sub></span> product presented in this study is useful for an improved understanding of changes in energy and water cycle on the TP. The dataset is freely available at the Science Data Bank (<a href="https://doi.org/10.11922/sciencedb.t00000.00010">https://doi.org/10.11922/sciencedb.t00000.00010</a>; Han et al., 2020b) and at the National Tibetan Plateau Data Center (<a href="https://doi.org/10.11888/Hydro.tpdc.270995">https://doi.org/10.11888/Hydro.tpdc.270995</a>, Han et al., 2020a).</p>