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Characterizing the diurnal patterns of errors in the prediction of evapotranspiration by several land‐surface models: An NACP analysis
Author(s) -
Matheny Ashley M.,
Bohrer Gil,
Stoy Paul C.,
Baker Ian T.,
Black Andy T.,
Desai Ankur R.,
Dietze Michael C.,
Gough Chris M.,
Ivanov Valeriy Y.,
Jassal Rachhpal S.,
Novick Kimberly A.,
Schäfer Karina V. R.,
Verbeeck Hans
Publication year - 2014
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1002/2014jg002623
Subject(s) - transpiration , evapotranspiration , vapour pressure deficit , environmental science , atmospheric sciences , flux (metallurgy) , latent heat , limiting , climatology , meteorology , geology , geography , chemistry , mechanical engineering , ecology , biochemistry , photosynthesis , organic chemistry , engineering , biology
Land‐surface models use different formulations of stomatal conductance and plant hydraulics, and it is unclear which type of model best matches the observed surface‐atmosphere water flux. We use the North American Carbon Program data set of latent heat flux (LE) measurements from 25 sites and predictions from 9 models to evaluate models' ability to resolve subdaily dynamics of transpiration. Despite overall good forecast at the seasonal scale, the models have difficulty resolving the dynamics of intradaily hysteresis. The majority of models tend to underestimate LE in the prenoon hours and overestimate in the evening. We hypothesize that this is a result of unresolved afternoon stomatal closure due to hydrodynamic stresses. Although no model or stomata parameterization was consistently best or worst in terms of ability to predict LE, errors in model‐simulated LE were consistently largest and most variable when soil moisture was moderate and vapor pressure deficit was moderate to limiting. Nearly all models demonstrate a tendency to underestimate the degree of maximum hysteresis which, across all sites studied, is most pronounced during moisture‐limited conditions. These diurnal error patterns are consistent with models' diminished ability to accurately simulate the natural hysteresis of transpiration. We propose that the lack of representation of plant hydrodynamics is, in part, responsible for these error patterns.