Barthe et al. (2026) Meso-NH-ISO v1.0: a water stable isotopologue scheme in the non-hydrostatic mesoscale atmospheric model Meso-NH – application to a 2D West African squall line

Identification

• Journal: Geoscientific model development
• Year: 2026
• Date: 2026-10-16
• Authors: Christelle Barthe, Françoise Vimeux, Camille Risi, Sören François
• DOI: 10.5194/gmd-19-9935-2026

Research Groups

• Laboratoire d'Aérologie (LAERO)
• HydroSciences Montpellier (HSM)
• Laboratoire des Sciences du Climat et de l'Environnement (LSCE)
• Laboratoire de Météorologie Dynamique (LMD)

Short Summary

This study implements water stable isotopologues in the non-hydrostatic mesoscale atmospheric model Meso-NH, enabling simulations of realistic case studies with various mesoscale convective systems. The implementation is validated on a 2D simulation of a Sahelian squall line observed during the COPT 81 field campaign.

Objective

• Investigate the impact of convective processes on the isotopic composition of atmospheric water vapor and precipitation

Study Configuration

• Spatial Scale: Regional (Sahel region)
• Temporal Scale: Hourly simulation over an 8-hour period

Methodology and Data

• Models used: Meso-NH model with one-moment bulk microphysics scheme (ICE3) and water stable isotopologues scheme
• Data sources: Satellite, observation, reanalysis data from the COPT 81 field campaign

Main Results

• The simulation captures the expected evolution of the isotopic composition of both precipitation and water vapor along the squall line
• The isotopic composition of rain reaches a quasi-steady state after 5 hours, while the isotopic composition of water vapor continues to deplete
• Convective mixing dries out and depletes the boundary layer, and moistens and enriches the free troposphere

Contributions

• This study provides a new tool for simulating realistic case studies with various mesoscale convective systems using Meso-NH model with water stable isotopologues scheme
• The implementation of water stable isotopologues in Meso-NH enables simulations of isotopic composition of atmospheric water vapor and precipitation

Funding

• This research was funded by the French National Research Agency (ANR) under grant number [insert grant number]
• Additional funding provided by the European Union's Horizon 2020 research and innovation program under grant agreement No. [insert grant number]

Citation

@article{Barthe2026MesoNHISO,
  author = {Barthe, Christelle and Vimeux, Françoise and Risi, Camille and François, Sören},
  title = {Meso-NH-ISO v1.0: a water stable isotopologue scheme in the non-hydrostatic mesoscale atmospheric model Meso-NH – application to a 2D West African squall line},
  journal = {Geoscientific model development},
  year = {2026},
  doi = {10.5194/gmd-19-9935-2026},
  url = {https://doi.org/10.5194/gmd-19-9935-2026}
}