A Vertically Discretised Canopy Description for ORCHIDEE (SVN R2290) and the Modifications to the Energy, Water and Carbon Fluxes. Naudts, K., Ryder, J., McGrath, M. J., Otto, J., Chen, Y., Valade, A., Bellasen, V., Berhongaray, G., Bönisch, G., Campioli, M., Ghattas, J., De Groote, T., Haverd, V., Kattge, J., MacBean, N., Maignan, F., Merilä, P., Penuelas, J., Peylin, P., Pinty, B., Pretzsch, H., Schulze, E. D., Solyga, D., Vuichard, N., Yan, Y., & Luyssaert, S. 7(6):8565–8647.
A Vertically Discretised Canopy Description for ORCHIDEE (SVN R2290) and the Modifications to the Energy, Water and Carbon Fluxes [link]Paper  doi  abstract   bibtex   
Since 70\,% of global forests are managed and forests impact the global carbon cycle and the energy exchange with the overlying atmosphere, forest management has the potential to mitigate climate change. Yet, none of the land surface models used in Earth system models, and therefore none of today's predictions of future climate, account for the interactions between climate and forest management. We addressed this gap in modelling capability by developing and parametrizing a version of the land surface model ORCHIDEE to simulate the biogeochemical and biophysical effects of forest management. The most significant changes between the new branch called ORCHIDEE-CAN (SVN r2290) and the trunk version of ORCHIDEE (SVN r2243) are the allometric-based allocation of carbon to leaf, root, wood, fruit and reserve pools; the transmittance, absorbance and reflectance of radiation within the canopy; and the vertical discretisation of the energy budget calculations. In addition, conceptual changes towards ãbetter process representation occurred for the interaction of radiation with snow, the hydraulic architecture of plants, the representation of forest management and ãnumerical solution for the photosynthesis formalism of Farquhar, von Caemmerer and Berry. For consistency reasons, these changes were extensively linked throughout the code. Parametrization was revisited after introducing twelve new parameter sets that represent specific tree species or genera rather than a group of unrelated species, as is the case in widely used plant functional types. Performance of the new model was compared against the trunk and validated against independent spatially explicit data for basal area, tree height, canopy strucure, GPP, albedo and evapotranspiration over Europe. For all tested variables ORCHIDEE-CAN outperformed the trunk regarding its ability to reproduce large-scale spatial patterns as well as their inter-annual variability over Europe. Depending on the data stream, ORCHIDEE-CAN had a 67 to 92\,% chance to reproduce the spatial and temporal variability of the validation data. [Conclusions] ORCHIDEE-CAN (SVN r2290) differs from the trunk version of ORCHIDEE (SVN r2243) by the allometric-based allocation of carbon to leaf, root, wood, fruit and reserve pools; the transmittance, absorbance and reflectance of radiation within the canopy; and the vertical discretisation of the energy budget calculations. Conceptual changes towards a better process representation were made for the interaction of radiation with snow, the hydraulic architecture of plants, the representation of forest management and a numerical solution for the photosynthesis formalism of Farquhar, von Caemmerer and Berry. Furthermore, these changes were extensively linked throughout the code to improve the consistency of the model. By making use of observation-based parameters the physiological realism of the model was improved and significant reparametrization was done by introducing twelve new parameter sets that represent specific tree species or genera rather than a group of phylogenetically often unrelated species, as is the case in widely used plant functional types (PFT). As PFTs have no meaning outside the modelling community, the species level parametrization of the ORCHIDEECAN branch can deliver actionable information to decision-makers and forest owners on the implications of management strategies on the climate. Model performance was tested against spatial explicit or upscaled data for basal area, tree height, canopy strucure, GPP, albedo and evapotranspiration over Europe. The tested data streams represented biogeochemical fluxes, biophysical fluxes and forest management related vegetation characteristics. Enhanced process representation in ORCHIDEE-CAN compared to the trunk version, was found to increase model performance regarding its ability to reproduce large-scale spatial patterns of all tested data streams as well as their interannual variability over Europe. Although this validation approach gives us confidence in the large-scale performance of the model over Europe, additional validation is recommended for other regional applications or higher resolution studies.
@article{naudtsVerticallyDiscretisedCanopy2014,
  title = {A Vertically Discretised Canopy Description for {{ORCHIDEE}} ({{SVN}} R2290) and the Modifications to the Energy, Water and Carbon Fluxes},
  author = {Naudts, K. and Ryder, J. and McGrath, M. J. and Otto, J. and Chen, Y. and Valade, A. and Bellasen, V. and Berhongaray, G. and Bönisch, G. and Campioli, M. and Ghattas, J. and De Groote, T. and Haverd, V. and Kattge, J. and MacBean, N. and Maignan, F. and Merilä, P. and Penuelas, J. and Peylin, P. and Pinty, B. and Pretzsch, H. and Schulze, E. D. and Solyga, D. and Vuichard, N. and Yan, Y. and Luyssaert, S.},
  date = {2014-12},
  journaltitle = {Geoscientific Model Development Discussions},
  volume = {7},
  pages = {8565--8647},
  issn = {1991-962X},
  doi = {10.5194/gmdd-7-8565-2014},
  url = {https://doi.org/10.5194/gmdd-7-8565-2014},
  abstract = {Since 70\,\% of global forests are managed and forests impact the global carbon cycle and the energy exchange with the overlying atmosphere, forest management has the potential to mitigate climate change. Yet, none of the land surface models used in Earth system models, and therefore none of today's predictions of future climate, account for the interactions between climate and forest management. We addressed this gap in modelling capability by developing and parametrizing a version of the land surface model ORCHIDEE to simulate the biogeochemical and biophysical effects of forest management. The most significant changes between the new branch called ORCHIDEE-CAN (SVN r2290) and the trunk version of ORCHIDEE (SVN r2243) are the allometric-based allocation of carbon to leaf, root, wood, fruit and reserve pools; the transmittance, absorbance and reflectance of radiation within the canopy; and the vertical discretisation of the energy budget calculations. In addition, conceptual changes towards ãbetter process representation occurred for the interaction of radiation with snow, the hydraulic architecture of plants, the representation of forest management and ãnumerical solution for the photosynthesis formalism of Farquhar, von Caemmerer and Berry. For consistency reasons, these changes were extensively linked throughout the code. Parametrization was revisited after introducing twelve new parameter sets that represent specific tree species or genera rather than a group of unrelated species, as is the case in widely used plant functional types. Performance of the new model was compared against the trunk and validated against independent spatially explicit data for basal area, tree height, canopy strucure, GPP, albedo and evapotranspiration over Europe. For all tested variables ORCHIDEE-CAN outperformed the trunk regarding its ability to reproduce large-scale spatial patterns as well as their inter-annual variability over Europe. Depending on the data stream, ORCHIDEE-CAN had a 67 to 92\,\% chance to reproduce the spatial and temporal variability of the validation data.

[Conclusions] ORCHIDEE-CAN (SVN r2290) differs from the trunk version of ORCHIDEE (SVN r2243) by the allometric-based allocation of carbon to leaf, root, wood, fruit and reserve pools; the transmittance, absorbance and reflectance of radiation within the canopy; and the vertical discretisation of the energy budget calculations. Conceptual changes towards a better process representation were made for the interaction of radiation with snow, the hydraulic architecture of plants, the representation of forest management and a numerical solution for the photosynthesis formalism of Farquhar, von Caemmerer and Berry. Furthermore, these changes were extensively linked throughout the code to improve the consistency of the model. By making use of observation-based parameters the physiological realism of the model was improved and significant reparametrization was done by introducing twelve new parameter sets that represent specific tree species or genera rather than a group of phylogenetically often unrelated species, as is the case in widely used plant functional types (PFT). As PFTs have no meaning outside the modelling community, the species level parametrization of the ORCHIDEECAN branch can deliver actionable information to decision-makers and forest owners on the implications of management strategies on the climate. Model performance was tested against spatial explicit or upscaled data for basal area, tree height, canopy strucure, GPP, albedo and evapotranspiration over Europe. The tested data streams represented biogeochemical fluxes, biophysical fluxes and forest management related vegetation characteristics. Enhanced process representation in ORCHIDEE-CAN compared to the trunk version, was found to increase model performance regarding its ability to reproduce large-scale spatial patterns of all tested data streams as well as their interannual variability over Europe. Although this validation approach gives us confidence in the large-scale performance of the model over Europe, additional validation is recommended for other regional applications or higher resolution studies.},
  keywords = {*imported-from-citeulike-INRMM,~INRMM-MiD:c-13586658,~to-add-doi-URL,climate,environmental-modelling,europe,featured-publication,forest-management,forest-resources,validation},
  number = {6}
}
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