Polcher et al. (2026) A framework to evaluate and identify development requirements for land‐surface models at km‐scale resolution: Application to a semi‐arid and mountainous region

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Identification

• Journal: Quarterly Journal of the Royal Meteorological Society
• Year: 2026
• Date: 2026-06-04
• Authors: Jan Polcher, Julie Collignan, Juan Pablo Sierra Perez, Gabriele Arduini, Sophie Bastin, Martin Best, Aaron Boone, Manel Bravo, Francesca Covella, Jasper M. C. Denissen, Cenlin He, Simon Munier, Marc Prange, Elena Shevliakova
• DOI: 10.1002/qj.70229

Research Groups

Not specified in the provided text.

Short Summary

This study evaluates six land-surface models (LSMs) at 3-km and 50-km resolutions in the Pyrenees, concluding that km-scale resolution requires the integration of lateral water transfers to accurately simulate evaporation and surface temperature.

Objective

• To evaluate whether increasing the spatial resolution of land-surface models (LSMs) to the km-scale provides the same benefits as it does for atmospheric and oceanic components, specifically regarding the representation of surface fluxes.

Study Configuration

• Spatial Scale: Regional scale (all catchments flowing off the Pyrenees), comparing 3-km resolution with 50-km resolution.
• Temporal Scale: Not specified in the provided text.

Methodology and Data

• Models used: Six different Land-Surface Models (LSMs).
• Data sources: High-resolution (3-km) atmospheric forcing data and reference simulations at 50-km resolution.

Main Results

• High-resolution (3-km) forcings successfully capture atmospheric contrasts between mountainous areas and valleys that are absent at 50-km resolution.
• At 3-km resolution, LSMs exhibit reduced evaporation over semi-arid catchments; this bias is attributed to the lack of spatial redistribution of water rather than atmospheric forcing differences.
• Models fail to reproduce local minima in land-surface temperature typically found along rivers and in irrigated areas.
• Lateral water transfers (groundwater, riparian recharge, and irrigation) are negligible at deca-kilometre scales but are essential for realistic surface flux predictions at km-scale resolutions.

Contributions

• The study identifies a critical limitation in current LSMs: the inability to represent landscape-organizing processes (lateral flows) at high resolutions, signaling a necessary shift in model development to include these processes for km-scale applications.

Funding

Not specified in the provided text.

Citation

@article{Polcher2026framework,
  author = {Polcher, Jan and Collignan, Julie and Perez, Juan Pablo Sierra and Arduini, Gabriele and Bastin, Sophie and Best, Martin and Boone, Aaron and Bravo, Manel and Covella, Francesca and Denissen, Jasper M. C. and He, Cenlin and Munier, Simon and Prange, Marc and Shevliakova, Elena},
  title = {A framework to evaluate and identify development requirements for land‐surface models at km‐scale resolution: Application to a semi‐arid and mountainous region},
  journal = {Quarterly Journal of the Royal Meteorological Society},
  year = {2026},
  doi = {10.1002/qj.70229},
  url = {https://doi.org/10.1002/qj.70229}
}