Cet article publié dans la revue Surveys in Geophysics démontre l’apport de plus de trente ans d’observations spatiales pour le suivi des eaux continentales en Afrique. Les forces et limitations des différents capteurs, ainsi que les perspectives proches (au travers de la mission SWOT notamment) et plus lointaines y sont exposées. Cet article est le fruit de collaborations entre pays Européens et pays du Sud. Il est disponible en libre accès ici.
Water Resources in Africa under Global Change: Monitoring Surface Waters from Space
ABSTRACT
The African continent hosts some of the largest freshwater systems worldwide, characterized by a large distribution and variability of surface waters that play a key role in the water, energy and carbon cycles and are of major importance to the global climate and water resources. Freshwater availability in Africa has now become of major concern under the combined effect of climate change, environmental alterations and anthropogenic pressure. However, the hydrology of the African river basins remains one of the least studied worldwide and a better monitoring and understanding of the hydrological processes across the continent become fundamental. Earth Observation, that offers a cost-effective means for monitoring the terrestrial water cycle, plays a major role in supporting surface hydrology investigations. Remote sensing advances are therefore a game changer to develop comprehensive observing systems to monitor Africa’s land water and manage its water resources. Here, we review the achievements of more than three decades of advances using remote sensing to study surface waters in Africa, highlighting the current benefits and difficulties. We show how the availability of a large number of sensors and observations, coupled with models, offers new possibilities to monitor a continent with scarce gauged stations. In the context of upcoming satellite missions dedicated to surface hydrology, such as the Surface Water and Ocean Topography (SWOT), we discuss future opportunities and how the use of remote sensing could benefit scientific and societal applications, such as water resource management, flood risk prevention and environment monitoring under current global change.
