Benchmarking a new urban scheme in the ORCHIDEE 2.2 land surface model
- 1ETH Zurich (Zurich, Switzerland)
- 2Laboratoire atmosphères, milieux, observations spatiales (Guyancourt, France)
- 3Milieux environnementaux, transferts et interactions dans les hydrosystèmes et les sols (Paris, France)
Abstract
Urban areas change natural surface energy and water balances, yet some land surface models still represent cities as natural surfaces. In this study, we present the development of a one-tile urban scheme for the ORCHIDEE land surface model, designed to improve the representation of urban processes, particularly for high-resolution applications. The scheme incorporates key urban parameters such as albedo, building height, thermal properties, and imperviousness. We propose a novel physically-based approach for representing imperviousness, by modifying saturated hydraulic conductivity to account for both surface and subsurface impacts. Off-line simulations across 20 urban flux tower sites show improved performance in sensible and latent heat fluxes with the new urban scheme, compared to the original baresoil representation. Mean absolute error (MAE) evaluation confirms improved model skill, aligning with benchmark results from the Urban-PLUMBER intercomparison. The scheme also captures expected urban hydrological signatures, such as increased surface runoff, though some reductions in subsurface runoff may be less consistent with observed urban recharge patterns. This work lays the foundation for applying ORCHIDEE at the basin scale and in high-resolution convection-permitting simulations for urban hydroclimate studies. Perspectives include refining thermal parameter choices, integrating anthropogenic heat fluxes, and conducting high-resolution simulations to assess hydrological performances using observed streamflow data.
Versions
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BibTeX
@article{lalonde2026benchmarking,
title = {{Benchmarking a new urban scheme in the ORCHIDEE 2.2 land surface model}},
author = {Morgane Lalonde and Sophie Bastin and Ludovic Oudin and Pedro Felipe Arboleda-Obando and Agnès Ducharne},
journal = {Geoscientific Model Development},
year = {2026},
month = oct,
doi = {10.5194/gmd-19-9463-2026},
url = {https://gmd.copernicus.org/articles/19/9463/2026/},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Benchmarking a new urban scheme in the ORCHIDEE 2.2 land surface model
AU - Morgane Lalonde
AU - Sophie Bastin
AU - Ludovic Oudin
AU - Pedro Felipe Arboleda-Obando
AU - Agnès Ducharne
PY - 2026
DA - 2026/10/07
JO - Geoscientific Model Development
DO - 10.5194/gmd-19-9463-2026
UR - https://gmd.copernicus.org/articles/19/9463/2026/
AB - Urban areas change natural surface energy and water balances, yet some land surface models still represent cities as natural surfaces. In this study, we present the development of a one-tile urban scheme for the ORCHIDEE land surface model, designed to improve the representation of urban processes, particularly for high-resolution applications. The scheme incorporates key urban parameters such as albedo, building height, thermal properties, and imperviousness. We propose a novel physically-based approach for representing imperviousness, by modifying saturated hydraulic conductivity to account for both surface and subsurface impacts. Off-line simulations across 20 urban flux tower sites show improved performance in sensible and latent heat fluxes with the new urban scheme, compared to the original baresoil representation. Mean absolute error (MAE) evaluation confirms improved model skill, aligning with benchmark results from the Urban-PLUMBER intercomparison. The scheme also captures expected urban hydrological signatures, such as increased surface runoff, though some reductions in subsurface runoff may be less consistent with observed urban recharge patterns. This work lays the foundation for applying ORCHIDEE at the basin scale and in high-resolution convection-permitting simulations for urban hydroclimate studies. Perspectives include refining thermal parameter choices, integrating anthropogenic heat fluxes, and conducting high-resolution simulations to assess hydrological performances using observed streamflow data.
SN - 1991-9603
SN - 1991-959X
ER -