Plant hydraulic transport controls transpiration sensitivity to soil water stress
نویسندگان
چکیده
Abstract. Plant transpiration downregulation in the presence of soil water stress is a critical mechanism for predicting global water, carbon, and energy cycles. Currently, many terrestrial biosphere models (TBMs) represent this with an empirical correction function (?) moisture – convenient approach that can produce large prediction uncertainties. To reduce uncertainty, TBMs have increasingly incorporated physically based plant hydraulic (PHMs). However, PHMs introduce additional parameter uncertainty computational demands. Therefore, understanding why when PHM ? predictions diverge would usefully inform model selection within TBMs. Here, we use minimalist to demonstrate coupling effects atmospheric demand leads spectrum responses controlled by soil–plant transport (conductance). Within transport-limitation spectrum, emerges as end-member scenario infinite conductance, completely decoupling on transpiration. As result, most systems low conductance (transport-limited) experience high variation moderate supply plants. We test these results using land surface at AmeriFlux site. At transport-limited site, scheme outperforms due its sensitivity variations demand. Based observation, develop new “dynamic ?” varies overcomes existing biases schemes has potential simplify parameterization implementation.
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ژورنال
عنوان ژورنال: Hydrology and Earth System Sciences
سال: 2021
ISSN: ['1607-7938', '1027-5606']
DOI: https://doi.org/10.5194/hess-25-4259-2021