Béland et al. (2026) Consideration of radiation absorption by stems in forests for microclimate modeling

Identification

• Journal: Geoscientific model development
• Year: 2026
• Date: 2026-09-24
• Authors: Martin Béland, Gordon B. Bonan, Hideki Kobayashi, Dennis Baldocchi
• DOI: 10.5194/gmd-19-9019-2026

Research Groups

• Digital Forest Lab, Department of Geomatics Sciences, Laval University, Quebec City, G1V 0A6, Canada
• NSF National Center for Atmospheric Research, Boulder, CO 80307, USA
• Institute of Arctic Climate and Environment Research, Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, 3173-25 Showamachi, Kanazawa-ku, Yokohama, 236-0001, Japan
• Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720, USA

Short Summary

This study modifies the radiative transfer component of the CanVeg2 multilayer canopy model to include radiation absorption by woody stems. The modified model is evaluated against a 3D ray tracing radiative transfer model and tower observations of albedo in four broadleaf forests.

Objective

• To develop a more generalizable approach to modeling radiation absorption by stems for use in microclimate models.
• To evaluate the effect of adding new functionalities like increased multiple scattering from leaf clumping or radiation absorption by wood on simulated and observed albedos.

Study Configuration

• Spatial Scale: Local scale, with four broadleaf forest sites used for evaluation.
• Temporal Scale: Diurnal patterns of albedo were calculated as the average albedo for each hour (or half-hour at the SERC and Pasoh sites) over a month.

Methodology and Data

• Models used: Modified Norman model, 3D ray tracing radiative transfer model FLiESvox.
• Data sources: Ground lidar data, tower-based observations of albedo, leaf optical properties measurements.

Main Results

• The modified Norman model shows good agreement with the 3D ray tracing model and tower observations of albedo in both NIR and PAR wave bands.
• Radiation absorption by stems is found to have a significant impact on simulated albedos, especially in the NIR.
• The consideration of multiple scattering within layers of clumped leaves also improves the correspondence between modeled and measured albedos.

Contributions

• This study provides a tractable and computationally efficient implementation of radiation absorption by woody stems for use in microclimate models.
• The modified Norman model shows improved performance compared to the original model, especially when considering radiation absorption by stems and multiple scattering within layers.

Funding

• Not specified.

Citation

@article{Béland2026Consideration,
  author = {Béland, Martin and Bonan, Gordon B. and Kobayashi, Hideki and Baldocchi, Dennis},
  title = {Consideration of radiation absorption by stems in forests for microclimate modeling},
  journal = {Geoscientific model development},
  year = {2026},
  doi = {10.5194/gmd-19-9019-2026},
  url = {https://doi.org/10.5194/gmd-19-9019-2026}
}