30 years of the AMMA-Catch Observatory: challenges and news from the "critical zone" in Africa

The rain is coming to the Sahel, at the beginning of the monsoon. © IRD/ Thierry Lebel

From 12th to 14th November 2018, Niamey is hosting the 30 years symposium of the hydrometeorological observatory on West Africa, AMMA-Catch

Organized with the support of the AGRHYMET regional centre and the Ministry of Higher Education, Research and Innovation of Niger (MESRI), this event is an opportunity to review the scientific and societal challenges about the water cycle and the "critical zone" in Africa.

The monsoon rhythm the life of the 300 million inhabitants of the Sahel. In less than four months, from June to September, it provides most of the annual rainfall. All crops and water resources, and therefore food security, depend on the intensity and duration of its rains.

Monsoon in the context of global warming

IRD scientists and their partners have been observing this capricious monsoon for 30 years to better understand its variability and evolution in a context of global warming. In particular, the AMMA-Catch observation system has enabled them to highlight certain characteristics and paradoxes of the water cycle associated with the African monsoon. "Such a system to observe the water cycle on a regional scale has no equivalent throughout sub-Saharan Africa, either in terms of duration, number of variables sampled or spatio-temporal resolution," says Thierry Lebel, hydroclimatologist at the IRD, who created the observatory in 1988.

Through 30 years of continuous observation, AMMA-Catch partners have data to identify significant climate trends in the region and detect the effects of different climate forcing factors (global warming trend; decadal ocean variability; interannual variability). This period is also very interesting for monitoring hydrological or environmental variables, such as land use.

A "critical area" under surveillance

At a time when various global changes are at work on the planet, AMMA-Catch's observations are now focusing on the "critical zone" of the Earth system, located between aquifers and the lower atmosphere, in which water flows. A better understanding of this area is crucial for humans, who live there, draws their resources from it and suffer from its hazards.

This "critical area" is at the heart of the conference organized in Niamey. The scientists will present their recent results on this theme. They will also discuss the means necessary to sustain the observation network for the next 10 years and the appropriation of these results by the decision-makers in charge of implementing environmental policies in the countries of the region.

An important expectation of the symposium will be to "make the hydro-eco-climatic documentation work carried out by the observatory better known, so that African institutions and scientists can take more of it as part of their scientific heritage," says Sylvie Galle, hydrologist at the IRD and current head of the AMMA-Catch observatory.

This article was published by the IRD. It has been translated in English by


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