CANVEG

Criterion	Explanation
General Description	Landscape scale biophysical 1-D multilayer gas exchange model between biosphere and atmosphere for CO₂, ¹³CO₂, water, sensible heat, ozone, sulfur dioxide, and isoprene flux densities using coupled micrometeorological and physiological modules.
Model Domain	General
Developer	University of California, Berkeley: Professor Dennis D. Baldocchi.
Hardware computing requirements	Not specified
Code language	Visual C++
Original application	Original model (CANOAK) was used to calculate fluxes of carbon dioxide, water vapor and energy between vegetation and the atmosphere in forest systems.
Public/proprietary and cost	Public, no associated cost for use.
Physically or empirically based	Mechanistic model based on net ecosystem exchange flux partitioning.
Mathematical methods used	Uses scalar conservation, algorithms, and sub-models to account for: micrometeorology, turbulence, diffusion, radiative transfer, net leaf exchange (photosynthesis, respiration, stomatal conductance and transpiration), soil exchange (soil and root respiration and evaporation). Additional information can be obtained from Baldocchi and Harley (1995), Baldocchi (1997) and Baldocchi and Meyers (1998).
Input data requirements	Photosynthetic photon flux density, air temperature, wind speed, relative humidity and CO₂ concentration, leaf area index, maximum carboxylation rate, leaf angle orientation, spatial dispersion index and canopy height, soil temperature at a deep reference point. Meteorological and soil data easily obtained from public databases, canopy characteristics can be assimilated with some effort from peer reviewed sources.
Outputs	Micrometeorological module output – environmental variables such as leaf and soil energy exchange, turbulent diffusion, scalar concentration profiles and radiative transfer within the canopy Physiological module output – leaf photosynthesis, stomatal conductance and respiration from leaf, bole, soil and roots. Complete model output – Gross primary productivity, net ecosystem exchange, respiration of total ecosystem and individual components for CO₂, H₂O and sensible heat.
Pre-processing and post-processing tools	No processing software provided.
Representation of uncertainty	Currently no error propagation or uncertainty limits integrated into model framework. Uncertainty of various computational methods have been evaluated using uncertainly in data input, fractionation factors, model parameters and making multiple iterations (Oikawa et al., 2017).
Prevalence	Currently used exclusively by individual modelers in academic institutions.
Ease of use for public entities	Moderate to difficult: experience with Visual C++ required.
Ease of obtaining information and availability of technical support	No commercial technical support, only correspondence with individual modelers can provide support.
Model and Source code availability	No model or source code readily available to public. Source code available upon request from developer.
Status of model development	Model developed and available for use. Future updates include expanding CANVEG model from ecosystem scale to continental and global scales using a more simplistic version of the model (to be named BESS model).
Challenges for integration	Integration challenges may include difficulties integrating with other models requiring 2-D or higher spatial resolution.

References

Baldocchi, D.D. and Harley, P.C., 1995. Scaling carbon dioxide and water vapour exchange from leaf to canopy in a deciduous forest. II. Model testing and application. Plant, Cell & Environment, 18(10), pp.1157-1173.

Baldocchi, D., 1997. Measuring and modelling carbon dioxide and water vapour exchange over a temperate broad‐leaved forest during the 1995 summer drought. Plant, Cell & Environment, 20(9), pp.1108-1122.

Baldocchi, D. and Meyers, T., 1998. On using eco-physiological, micrometeorological and biogeochemical theory to evaluate carbon dioxide, water vapor and trace gas fluxes over vegetation: a perspective. Agricultural and Forest Meteorology, 90(1-2), pp.1-25.

Oikawa, P.Y., Sturtevant, C., Knox, S.H., Verfaillie, J., Huang, Y.W. and Baldocchi, D.D., 2017. Revisiting the partitioning of net ecosystem exchange of CO 2 into photosynthesis and respiration with simultaneous flux measurements of 13 CO 2 and CO 2, soil respiration and a biophysical model, CANVEG. Agricultural and forest meteorology, 234, pp.149-163.

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