The AMMA-CATCH soil moisture measurement networkM. Grippa1, P. de Rosnay2, T. Pellarin3, C. Gruhier1, F. Timouk1, S. Galle3, B. Cappelaere4, J. Demarty4, C. Peugeot4, M. Zribi1, E. Mougin1, L. Kergoat1, F. Baup1, Y. Kerr1, T. Lebel3

1- Centre d’Etudes Spatiales de la BIOsphère (CESBIO), Toulouse, France 2- European Centre for Medium-Range Weather Forecasts (ECMWF), Reading, UK3- Laboratoire d'Etude des Transferts en Hydrologie et Environnement (LTHE), Grenoble, France 4- Hydro Science Montpellier (HSM), Montpellier, France

The AMMA-CATCH observatory

Cal-Val SMOS AMMA over West Africa

• Validation of SMOS soil moisture products: comparing SMOS products with both simulated and observed soil moisture at different scales. • Validation of retrieval algorithms: forward modelling of brightness temperature from both observed and simulated SM from local scale to meso-scale• Assimilation in Land Surface Models: retrieve the root zone soil moisture. Multi-model approach.

The coordination of the SMOS-AMMA Cal-Val is organised between ESA and CNES (TOSCA proposal), the latter assuring themaintentance of the soil moisture measurement network.

Fluxes

Comparison to remote sensing soil moisture products

Ground measurements

Upscaling soilmoisturemeasurements

Soil moisture

3 mesoscale sites in Mali, Niger and Benin that sample across the 100-1300 mm/annum rainfall gradient of the Sahel, Sudan and North-Guinean bioclimatic zones

North Sahelian climate (between isohyets 400 and 100 mm). Semi-arid natural vegetation composed of annual grasses and a sparse tree layer

South Sahelian climate with semi-arid vegetation and crops (millet, fallows and Tiger bush)

Soudanian climate (different types of rain systems) and Guinean savanna vegetation.

150 automaticrainguage stations

Surface hydrology

~ 30 linminimeters

14 H20 flux stations

7 CO2 stations

120 CS615/616 (Campbell) between

5 cm and 3 m

10 thetaprobes

1 km to 50 km transects withportable thetaprobes

30 soil moistureprofiles

Mali site

Niger siteBenin site

Contexte

Surface soil moisture estimated from transect measurements at 1km scale and from local measurements at the Agoufou station at which the following up-scaling relation was applied:

SSM 1km = -0.68855+ 1.7561xSSMlocal

De Rosnay et al, JoH, 2009

Active microwaves

ENVISAT-ASAR derived soil moisture (for acquistions at low incidence angle) compared to ground measurements at the Agoufou malian site

Baup et al, RSE, 2007

ERS and ASAR soil moisture products and ground data comparison over the Niger site

Zribi et al., JoH, 2009

Local site

Local site

Meso site

Meso site

Local site

Meso site

Passive microwaves

AMSR-E soil moisture products evaluation by comparison to ground measurements over the AMMA-CATCH sites

See poster L2SM, Gruhier et al