i initiative

Space and Development…Increasing Access to Space in Africa

Dust and Droughts in Africa

Posted by Simon Adebola on August 20, 2009

The plight of African farming and the need to develop adaptive systems to cope with the changes that may be forced on African populations due to environmental change has been touched on in an earlier post. The role that early warning systems can play in shaping this adaptive response has also been discussed in another post. This post has as its focus an examination of the interactions, as often abound in nature, between factors in the African environment, and how these interactions could contribute to the challenges being faced with precipitation, drought and food security. The role of space science and technology in arming researchers, scientists and government policy makers with the right information and predictive tools to evolve appropriate and evidence-based responses to these challenges is highlighted.

The flow of dust on the African continent is abundant. It has some of the world’s largest sandy deserts- the Sahara (the world’s largest hot desert), the Kalahari and the Namib. The Arabian desert extending from Egypt to Iran is also close by. These supply a stream of dust propelled by the trade winds and which blow huge amounts of dust over the continent towards the equator and the oceans. The effect of these dusty winds on rainfall is by acting as aerosols and interfering with the coalescing of water droplets in rain clouds. This leads to a dispersion effect on the water droplets, preventing rain drop formation and hence precipitation. The scourge of reducing annual rainfall on many parts of the African continent is as shown in the picture below. The socio-economic impact of this is better avoided. Food and water shortages in Kenya this year left about a third of the population in need of aid.

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Drought in Africa 2009 (Source: NASA Earth Observatory)

Another effect of dust clouds is on Sea Surface Temperature (SST) and its ensuing effect on tropical storms. Although not a major problem for the continent on its Atlantic end, the propagation of El Niño-La Niña events has been linked to droughts, tropical rainfall, storms, floods, malaria and even cholera incidence in some parts of Africa. The El Niño Southern Oscillation (ENSO) also bears links to other diseases. Space technologies play a crucial part in defining and predicting the occurence of these events and may also aid the mitigation process.
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Atlantic Ocean Temperatures at End of June 2009 (Source: NASA Earth Observatory)

Aerosol Optical and Dynamic Propoerties (Source: NASA Goddard)

Amongst other uses of space technologies in keeping track of these environmental variables, their use in monitoring groundwater has also been demonstrated. Using results from the Gravity Recovery and Climate Experiment (GRACE) a joint NASA and DLR mission, a team of NASA researchers demonstrated receeding groundwater stores in India, most likely due to irrigation that has relied on these groundwater sources. Thus using satellite technology it is now possible to generate a comprehensive monitoring system that keeps track of not only the environmental variables affecting precipitation and drought, but also the effectiveness and effect of countermeasures developed as part of the anti-drought response.

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2 Responses to “Dust and Droughts in Africa”

  1. This is bad condition for farmers, they should adopt new techniques to cope with this.

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