In explaining and predicting spatial vegetation patterns, ecologists have increasingly favoured the use of climatic water balance variables, including actual evapotranspiration (AET) and climatic water deficit (CWD), for representing the hydrologic and energetic environment experienced by plants. Much of the interest in these variables lies in their hypothesized potential to characterize biologically relevant environmental variation more directly than simple climate variables, such as precipitation and temperature. Practically, obtaining AET and CWD values across space requires hydrologic process models that involve assumptions, including assumptions about vegetation transpiration rates. However, transpiration parameter values are rarely known with precision and can vary several‐fold within and among vegetation types.

中文翻译：

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气候水平衡用于生态推断的效用取决于植被生理学假设

在解释和预测空间植被格局时，生态学家越来越倾向于使用气候水平衡变量（包括实际蒸散量（AET）和气候缺水量（CWD））来表示植物所经历的水文和能量环境。这些变量的大部分兴趣在于它们的潜在潜力，与简单的气候变量（例如降水和温度）相比，它们更直接地表征生物学相关的环境变化。实际上，获得整个空间的AET和CWD值需要水文过程模型，该模型涉及各种假设，包括有关植被蒸腾速率的假设。但是，很少精确地了解蒸腾参数值，并且在植被类型之间和之中可能会发生几倍的变化。