Multi-decadal trends in global terrestrial evapotranspiration and its components.
Multi-decadal trends in global terrestrial evapotranspiration and its components.
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DOI：
10.1038/srep19124
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发表时间：
2016-01-11
影响因子：
4.6
通讯作者：
Pan M
中科院分区：
文献类型：
--
作者：
Zhang Y;Peña-Arancibia JL;McVicar TR;Chiew FH;Vaze J;Liu C;Lu X;Zheng H;Wang Y;Liu YY;Miralles DG;Pan M
蒸散（ET）是液态水变成水蒸气的过程，从能量角度来说，它在很大程度上消耗了入射的太阳辐射。如果没有蒸散过程，气温将会更高，因此了解蒸散趋势对于预测未来气温至关重要。近期研究报告称，近几十年来蒸散量长期下降，尽管这些下降可能与气候多变性有关。在此，我们使用一个经过充分验证的诊断模型来估算1981 - 2012年期间的每日蒸散量及其三个组成部分：植被蒸腾（Et）、土壤直接蒸发（Es）以及植被截留降雨的汽化（Ei）。在此期间，陆地蒸散量显著增加（p < 0.01），这是由Et和Ei的增加所导致的，而Es的下降部分抵消了这种增加。这些相反的趋势主要是由植被叶面积指数的增加所驱动的，而植被叶面积指数的增加以绿化为主。陆地Et的总体增加量大约是Es减少量的两倍。大多数耦合模式比较计划第5阶段（CMIP5）的模型都没有模拟出这些相反的趋势，这凸显了在地球系统模型中真实地呈现植被变化对于预测能量和水循环未来变化的重要性。
Evapotranspiration (ET) is the process by which liquid water becomes water vapor and energetically this accounts for much of incoming solar radiation. If this ET did not occur temperatures would be higher, so understanding ET trends is crucial to predict future temperatures. Recent studies have reported prolonged declines in ET in recent decades, although these declines may relate to climate variability. Here, we used a well-validated diagnostic model to estimate daily ET during 1981–2012, and its three components: transpiration from vegetation (Et), direct evaporation from the soil (Es) and vaporization of intercepted rainfall from vegetation (Ei). During this period, ET over land has increased significantly (p < 0.01), caused by increases in Et and Ei, which are partially counteracted by Es decreasing. These contrasting trends are primarily driven by increases in vegetation leaf area index, dominated by greening. The overall increase in Et over land is about twofold of the decrease in Es. These opposing trends are not simulated by most Coupled Model Intercomparison Project phase 5 (CMIP5) models, and highlight the importance of realistically representing vegetation changes in earth system models for predicting future changes in the energy and water cycle.