Comparing Model Representations of Physiological Limits on Transpiration at a Semi‐Arid Ponderosa Pine Site
Comparing Model Representations of Physiological Limits on Transpiration at a Semi‐Arid Ponderosa Pine Site
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DOI：
10.1029/2021ms002927
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发表时间：
2022-01
影响因子：
6.8
通讯作者：
L. Hawkins;Maoya Bassouni;W. Anderegg;M. Venturas;S. Good;H. Kwon;C. Hanson;R. Fiorella;G. Bowen;C. Still
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作者：
L. Hawkins;Maoya Bassouni;W. Anderegg;M. Venturas;S. Good;H. Kwon;C. Hanson;R. Fiorella;G. Bowen;C. Still
生态系统模型中生物地球化学过程的机制表征正在迅速发展，这需要模型评价方法的进步。在这里，我们量化了模型功能性能的多个方面，以评估生态系统模型中改进的过程表示。我们使用一套指标和分析工具，比较了具有水力约束的半经验气孔模型与半干旱松林的气孔和水力功能的更机械表征。我们发现模型在无应力条件下的表现大致相似，但在大气和土壤干旱条件下的表现不同。经验模型能更好地捕捉土壤水势和蒸腾水汽压亏缺之间的协同信息流，而机制模型则过于确定。虽然模型可以参数化以产生类似的功能性能，但交替的参数化不能克服低估土壤水势中关于蒸腾的独特信息的结构模型约束。此外，多层冠层模型和大叶片模型都无法捕捉到冠层温度与空气温度差异的大小，并且我们证明了叶片温度的误差可以传播到模拟蒸腾的相当大的误差。这项研究证明了将未充分利用的观测数据流与新兴的分析工具相结合，以表征生态系统功能和区分模型过程表示的价值。
Mechanistic representations of biogeochemical processes in ecosystem models are rapidly advancing, requiring advancements in model evaluation approaches. Here we quantify multiple aspects of model functional performance to evaluate improved process representations in ecosystem models. We compare semi‐empirical stomatal models with hydraulic constraints against more mechanistic representations of stomatal and hydraulic functioning at a semi‐arid pine site using a suite of metrics and analytical tools. We find that models generally perform similarly under unstressed conditions, but performance diverges under atmospheric and soil drought. The more empirical models better capture synergistic information flows between soil water potential and vapor pressure deficit to transpiration, while the more mechanistic models are overly deterministic. Although models can be parameterized to yield similar functional performance, alternate parameterizations could not overcome structural model constraints that underestimate the unique information contained in soil water potential about transpiration. Additionally, both multilayer canopy and big‐leaf models were unable to capture the magnitude of canopy temperature divergence from air temperature, and we demonstrate that errors in leaf temperature can propagate to considerable error in simulated transpiration. This study demonstrates the value of merging underutilized observational data streams with emerging analytical tools to characterize ecosystem function and discriminate among model process representations.