Climate Exchange

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Partnerships on water resource

management in France

Philippe Dandin, François Besson, Michèle Blanchard, Jean-Pierre Céron, Laurent Franchistéguy, Fabienne

Rousset-Regimbeau, Jean-Michel Soubeyroux, Météo-France, Direction de la Climatologie;

Martine Baillon, Ministère de l’Ecologie, du Développement Durable et de l’Energie, SCHAPI;

Jean-Philippe Vidal, Institut National de Recherche en Sciences et Techniques pour l’Environnement et l’Agriculture;

Stéphanie Singla, Eric Martin, Météo-France and CNRS, Centre National de Recherches Météorologiques;

Florence Habets, CNRS, UMR Sisyphe UPMC, Mines ParisTech

n order to improve weather forecasts, meteorological models

have been gradually sophisticated and most operational

suites nowadays include a full representation of surface

conditions – oceans, continental surfaces and snow, ice or

glaciers – as well as of the coupling with the atmosphere.

Interactive Soil-Vegetation-Atmosphere Transfer (SVAT) models

are embedded in numerical weather forecast or climate models.

Such systems compute the interplay between the bottom part of the

atmosphere and the upper part of the soil: they describe in detail

the surface conditions of primary interest for water management.

They can be activated in various modes, covering a large spec-

trum of applications from a long-term reanalysis to

daily monitoring of surface conditions, short range to

seasonal forecasting or secular climate scenarios. A rich

set of products and services can therefore be delivered

by meteorological and climatological services to water

resource managers, adding to a routine approach the

other critical dimensions that enrich dialogue and create

the real value of the service – getting useful support

in the event of a crisis as well as receiving valuable

elements for short-term (daily and weekly), mid-term

(monthly and seasonally) or long-term (climate scenar-

ios) planning. The availability of a comprehensive set

of products covering all time and space scales relevant

to water monitoring is highly appreciated by different

users, which receive the tailored information immedi-

ately available in their own information systems.

An interactive SVAT hydrology suite called Safran-

Isba-Modcou (SIM) has been developed in the research

department at Météo-France, in close cooperation with

the hydrological research community. It was initially

meant for improving weather forecasts but it would

obviously serve other objectives. Safran performs an

analysis of eight essential atmospheric parameters.

Isba is a SVAT model and Modcou a distributed hydro-

logical model over all French catchments. Interestingly

the Isba-Modcou pair can be driven by various atmos-

pheric forcings from a reanalysis to short- or mid-term

numerical weather forecasts, to seasonal forecasts and

climate scenarios – provided a suitable downscaling

is applied to the large-scale fields.

SIM is first of all a community model (Météo-France,

Mines Paris Tech, Irstea) developed by scientists and

benefiting from regular upgrades by research labo-

ratories over the past 20 years.

Many studies have

been carried out with this suite, giving good confi-

dence in its behaviour under various circumstances.

Interestingly, SIM is used daily in the operational

suites of the meteorological service, Météo-France.

SIM is integrated every day, rerun at day+1 in order to

ater

A time sketch showing the evolution of the Soil Wetness Index for a French

region (red) in 2012, with climatological references