陆地生态系统蒸腾蒸散比量化及其时空异质性研究进展

Advances in Quantifying the Ratio of Transpiration to Evapotranspiration in Terrestrial Ecosystems and Its Spatiotemporal Heterogeneity

蒸腾蒸散比(T/ET)是阐明陆地生态系统水分散失过程中植被作用的关键参量,蒸散及其组分的准确量化是生态水文研究的基础,有助于理解蒸散与气候变化的相互作用机制。总结了国内外T/ET观测和模拟方法及其量化结果的差异,梳理了森林、草原、湿地和农田4种陆地生态系统T/ET的研究成果,阐述了不同类型陆地生态系统T/ET的时空异质性及其驱动因素。不同生态系统T/ET的差异来源于生态系统特性、时空差异、观测方法和模型或数据集选取,但各差异来源对其的贡献率还未有统一定论;T/ET的变化主要依赖于生态类型、冠层特征、气候、土壤等条件,不同时空尺度的生态系统T/ET驱动因素不同。因此,针对T/ET量化方法开展不确定研究,阐明不同陆地生态系统T/ET的时空异质性,揭示其变化规律及驱动机制将是未来的研究重点。

The ratio of transpiration to evapotranspiration(T/ET)is a key parameter to illustrate the role of vegetation in controlling water loss in terrestrial systems.Quantifying evapotranspiration and its components is a key to understand the dynamics and mechanism of evapotranspiration and it is the basis for studying the eco-hydrological process.This paper reviews the research progress of T/ET quantification methods(measurement methods and model methods),T/ET results in different ecosystems and their driving mechanisms(climate change and vegetation cover).The methods are introduced in T/ET observation and simulation developed at home and aboard,and the results of different methods are compared.The values of T/ET are described in four types of terrestrial ecosystems,including forest,grassland,wetland and farmland.There are significant differences in T/ET in the same or even in the different ecosystems,which are mainly due to the differences in ecosystem types,spatial and temporal scales,selection of data set,observation and simulation methods.The main driving mechanisms of T/ET included vegetation type,vegetation cover,climate factors and soil factors.In the future,uncertainty studies around different quantification methods of T/ET,changing patterns and driving mechanisms of T/ET in different terrestrial ecosystems will be emphasized.