气候变化对科尔沁沙地蒸散发和植被的影响

Simulated impacts of climate change on evapotranspiration and vegetation in Horqin Sandy Land

近30年来科尔沁沙地的植被呈现显著退化,揭示气候变化下科尔沁沙地关键生态水文过程(如蒸散发和植被)的变化特征及其影响对荒漠化防治具有重要意义。本研究开发了水文过程与植被生长耦合的生态水文模型(WaVEM),模拟解析了科尔沁沙地各气象因子变化对实际蒸散发和植被变化的影响程度,探讨了气候变化下科尔沁沙地植被变化的响应规律。结果表明,1964—2013年间,在降水变化不显著而气温显著升高情况下,实际蒸散发和年最大叶面积指数均未发生显著变化。降水的年际变化是导致实际蒸散发和植被变化的主要因素,潜在蒸发的影响次之。短期的干旱会导致植被锐减,而短期干旱结束后植被能够迅速恢复;多年连续干旱是导致科尔沁植被显著退化的主要因素。

Vegetation degraded significantly in Horqin Sandy Land over the past three decades. Identifying the variability of the key ecohydrological processes （such as evapotranspiration and vegetation growth） that are closely related to desertification is prerequisite for a better control of desertification processes in the fu- ture. Based on an ecohydrological cellular automata model, the Water and Vegetation Interactions-based Eco-hydrological Model （WaVEM） was developed and employed to evaluate the effects of the precipitation and potential evapotranspiration changes on the actual evapotranspiration （Et ） and leaf area index, and to analyze the responses of vegetation to the multi-year precipitation reduction. During 1964--2013, Et and an- nual maximum LAI （LAI~,x） had insignificant trends while precipitation changed insignificantly and potential evapotranspiration increased significantly. The precipitation change was the major factor causing the decreas- es of both E, and LAI while the effect of potential evapotranspiration was the second. Multi-year precipi- tation reduction during 1999--2011 caused significant vegetation degradation in Horqin sandy land. A short-term drought could lead to a sudden decline in vegetation, however, vegetation recovered quickly af- ter the drought.