SURFEX

SURFEX is a land-surface modelling framework developed by Météo-France that provides a modular set of schemes for representing surface processes in numerical weather prediction and climate models. It is designed to be coupled with atmospheric models to exchange energy, water, and momentum at the interface between the land and the atmosphere. The goal is to offer a flexible, interoperable platform for testing and deploying different land-surface representations across models and resolutions.

The architecture of SURFEX comprises a core framework together with multiple surface schemes and packages. It supports both offline (uncoupled) runs and online simulations that are coupled to atmospheric models. The framework hosts several land-surface schemes, most notably ISBA (Interactions between Soil, Biosphere, and Atmosphere) and ORCHIDEE, as well as modules for urban surfaces, lakes, snow, and vegetation. These components simulate soil moisture, heat transfer, snow dynamics, energy balance, vegetation processes, and, in some configurations, carbon fluxes.

Typical inputs include climate forcings such as precipitation, radiation, and air temperature, as well as soil properties, land-use data, and vegetation characteristics (e.g., leaf area index and fractional cover). Outputs commonly encompass surface energy and water fluxes, soil moisture and temperature near the surface, snow cover, and albedo, among others. SURFEX is used to support both research and operational applications, enabling comparison of different surface representations and their impact on atmospheric simulations. The project is supported by Meteo-France and is documented for use by the wider meteorological and climate research community.