林分耗水的尺度扩展研究进展

蒸散耗水是森林生态系统水分循环过程的主要构成,是现代生态水文研究的重点和难点。直接测定和尺度上推提供了两种获取蒸散量的技术手段。受限于复杂的冠层结构、非均质的下垫面和迥异的环境条件,直接测定难以准确获取林分水平的耗水信息,因此有必要讨论单木与冠层结构、环境因子之间的耦合关系,利用时空尺度扩展得到合理的耗水量。本文综述了理论基础相对牢固的3种尺度扩展技术:基于生物计量参数、遥感影像和水文模型的尺度扩展,剖析各模型的控制因子,探讨模型的适用性和优缺点,对尺度扩展技术的发展做了展望。

Advance in the application of upscaling methods to stand evapotranspiration

Evapotranspiration is one of the main components of forest ecosystem hydrologic cycle, being an emphasis and a difficulty in the research of eco-hydrology. Direct measurement and upscaling are the two technical methods for estimating evapotranspiration. However, controlled by the complicated canopy architecture, heterogeneous underlying surface, and complex environment, it is hard to estimate forest stand evapotranspiration directly. Consequently, it is necessary to understand the coupling relationships between the water consumption by single tree and the canopy architecture and environmental parameters to acquire the forest stand rational water consumption through temporal and spatial upscaling. This paper summarized three upscaling methods whose theoretical foundation has been well developed, i.e., scaling up based on biometric parameters, scaling up based on remote sensing images, and scaling up based on hydrologic models, analyzed the controlling parameters of the three methods, and discussed the applicability and the advantages and disadvantages of the methods. The further development trends of upscaling were also prospected.