Lalonde et al. (2026) Benchmarking a new urban scheme in the ORCHIDEE 2.2 land surface model

Identification

• Journal: Geoscientific model development
• Year: 2026
• Date: 2026-10-07
• Authors: Morgane Lalonde, Sophie Bastin, Ludovic Oudin, Pedro Arboleda, Agnès Ducharne
• DOI: 10.5194/gmd-19-9463-2026

Research Groups

• LATMOS/IPSL, UVSQ Université Paris-Saclay, Sorbonne Université, CNRS, Guyancourt, France
• Sorbonne Université, CNRS, EPHE, UMR METIS, Paris, France
• Institute for Atmospheric and Climate Science, ETH Zürich, Zurich, Switzerland

Short Summary

This study presents the development of a one-tile urban scheme for the ORCHIDEE land surface model to improve the representation of urban processes. The new scheme incorporates key urban parameters such as albedo, building height, thermal properties, and imperviousness.

Objective

• To design an urban one-tile scheme that captures the dominant controls on the urban surface energy and water budgets while remaining consistent with ORCHIDEE's existing structure and computational constraints.
• To introduce a parsimonious, physically motivated representation of imperviousness in the urban soil tile.

Study Configuration

• Spatial Scale: Grid cell scale (kilometer-scale)
• Temporal Scale: Daily to annual time scales

Methodology and Data

• Models used: ORCHIDEE version 2.2 land surface model
• Data sources: Satellite data, observation, reanalysis

Main Results

• The new urban scheme improves the representation of sensible and latent heat fluxes compared to the original baresoil representation.
• The scheme captures expected urban hydrological signatures such as increased surface runoff.

Contributions

• This study contributes to the development of a physically based urban scheme in GCM-oriented LSMs, addressing the limitations of current urban representations.
• The new scheme provides improved performance in simulating local-scale fluxes for large-scale applications.

Funding

• Not specified

Citation

@article{Lalonde2026Benchmarking,
  author = {Lalonde, Morgane and Bastin, Sophie and Oudin, Ludovic and Arboleda, Pedro and Ducharne, Agnès},
  title = {Benchmarking a new urban scheme in the ORCHIDEE 2.2 land surface model},
  journal = {Geoscientific model development},
  year = {2026},
  doi = {10.5194/gmd-19-9463-2026},
  url = {https://doi.org/10.5194/gmd-19-9463-2026}
}