The Rhone-AGGregation (Rhone-AGG) Soil-Vegetation-Atmosphere-Transfer (SVAT) model intercomparison project is an initiative within the GEWEX/GLASS (Global Land-Atmosphere System Study : Polcher et al. 2000)/GSWP (Global Soil Wetness Project : Dirmeyer et al. 1999) panel of the WCRP. This project makes use of the Rhone modeling system, which was developed in recent years by the French research community1. Three distinct components comprise this system: a distributed hydrological model, an analysis system to determine the near-surface atmospheric forcing and a SVAT model interface. The coupling between the three components of the system is 1-way. It was created in an attempt to ensure a consistent dialogue between the atmospheric (precipitation, radiative fluxes, state variables) and the hydrological variables (evaporation, soil moisture, runoff, ground water and river flow) on a regional scale. The system utilizes high spatial resolution European soil and vegetation databases, but it has been designed such that it is transferable to other regions.

    The entire Rhone model domain size is on the order of that of a coarse-resolution Global atmospheric Climate Model (GCM), but the atmospheric forcing, the soil and vegetation parameters, and the observed river discharges are available at a significantly higher spatial resolution. It is then of interest to examine how the simulations from a wide range of SVAT schemes, which are used in GCMs, Numerical Weather Prediction (NWP) models, mesoscale atmospheric models or hydrological models, are impacted by changing the spatial resolution over the domain. The main goals of the Rhone-AGG are then to examine how various state of the art SVAT schemes are able to simulate the river discharge over several annual cycles when inserted into the Rhone modeling system, and to explore the impact of the various scaling or aggregation methods on the simulation of certain components of the hydrological cycle (such as snow cover and surface runoff). A limited number of multi-year (four total) experiments have been developed in an attempt to adequately address the posed science questions. The simulation time period (August, 1985, through July, 1989) was also selected in order to coincide with the GSWP experiments (1987-1988).

GSWP logo
Global Soil
Wetness Project
GLASS logo

    1 The authors would like to thank all their colleagues at the many French laboratories which have participated in the development of the Rhone modeling system. This work was supported by the program National d'Etude du Climat (PNEC), and by the Program National de Recherches en Hydrologie (PNRH). The Institut Francais d'ENvironnement (IFEN), Institut National Recherche Agronomique (INRA), the Banque Hydrologie, the French Environment Ministry and Météo-France provided the land-cover, soil, river flow and atmospheric data bases. The GEWEX-Rhone group consists of Météo-France (GMME: Group de Météorologie de Moyenne Echelle and CEN: Centre d'Etudes de la Neige), Centre Informatique et G\'eographique (CIG), Centre d'Etude du Machinisme Agricole, du Génie Rural, des Eaux et Forets (CEMAGREF), Centre d'etude des Environnements Terrestre et Planétaire (CETP), Laboratoire d'etude des Transferts en Hydrologie et Environnement (LTHE) and Bureau de Recherches Géologiques et Minieres (BRGM).

Related Links (on the MC2 web site in alphabetical order):

| GICC-Rhone | ISBA-MODCOU Rhone simulation | Rhone 14-year study |

Other Land-Surface Model Intercomparison Related Sites

| ALMA | GLASS | GSWP | LDAS | PILPS | PILPS-Phase 2e | SnowMIP |

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