AMMA-CATCH

AMMA-CATCH is a hydrological and meteorological observatory on West Africa. This national observation service (SNO) is dedicated to long-term monitoring of climatological, hydrological and ecological changes in West Africa. For this purpose, it gathers data from three mesoscale sites, which cover areas ranging between 10000 and 25000 km². The three sites are located at different latitudes so as to sample the characteristic eco-climatic gradients of West Africa. The first measures started in 1990.

Simultaneous monitoring of the vegetation cover, the phenology and the various terms of the water balance (rainfall, infiltration, groundwater recharge, surface runoff, evapotranspiration) at the three mesoscale sites provides insight into the interactions between the water cycle, vegetation dynamics and climate variability at intraseasonal and interannual scales over this region that is highly vulnerable to the impacts of global change.

The three meso-scale sites instrumented by the AMMA-CATCH observatory are located:

• in the pastoral Sahel (Gourma site, Mali and Ferlo, Senegal)• in the cultivated Sahel (Niamey Square Degree, Niger)

• in Sudanian climate (upper Ouémé watershed, Benin)

The average annual rain is 300 mm (Mali and Senegal), 600 mm (Niger) and 1200 mm (Benin) respectively, which is a doubling of rainfall between each site. This variability in rainfall induces a large variation in associated natural vegetation and cropping systems. Within each mesoscale site, the physical processes and the water balance closure are studied on supersites (~ 100 km²) while the main representative vegetation covers are examined at local intensive sites. In addition to basic measurements, these local intensive sites monitor meteorological, soil moisture and turbulent (sensible, H2O, CO2) flux data. In total, the AMMA-CATCH observation network records 2500 measurements per hour.

Reference scientific article : AMMA-CATCH studies in the Sahelian region of West-Africa: An overview.