UK, March 13, 2015: An international research team led by the University of Leicester has mapped the entire African continent south of the Sahara for geographical changes. The researchers observed that areas such as the Congo, Nigeria and Madagascar now receive far less rainfall than they did a decade ago, while other locations such as the Sahel zone have become far greener through increased rainfall.
Together with the Joint Research Centre of the European Commission, the Institute of Electromagnetic Sensing of Environment of the National Research Council of Italy, and the Polish Institute of Geodesy and Cartography, the study analysed 10 years of satellite data.
Professor Heiko Balzter, Director of the Centre for Landscape and Climate Research at the University of Leicester and co-author of the study, said: “We looked at the satellite data and discovered a number of surprising hotspots of change. Some parts of the Congo, Nigeria and Madagascar appear to receive much less rainfall now compared to 10 years ago. This is an issue even in the wet tropics of the Congo, where low rainfall means restrictions to ship movements on the rivers there, which are the main transport routes in the dense jungle.
“This means that our maps cannot be regarded as maps of long-term climate change impacts. They merely reflect climatic impacts over the past ten years. We know that this period is too short to relate it to the global warming debate. Future satellite observations will allow us to extend the time-series and observe large-scale changes in Africa.”
Regions where more rainfall led to greener plants were mapped in West Africa, Central African Republic, West Cameroon and north-eastern part of South Africa. Areas of climatic vegetation degradation were located in Southern Madagascar, Nigeria, Kenya and the Garden Route region of South Africa.
The researchers used a rain dataset that is produced by the National Oceanic and Atmospheric Administration’s (NOAA) Climate Prediction Centre and combined the qualities of local rain gauge stations with the satellite data. The system is used by the US for a famine early warning system.
The new concept developed by the research team interprets satellite observations of rainfall and vegetation greenness at the same time. If the plants lost some of their greenness over time, then the researchers checked for climatic changes, meaning reduced rainfall. If reduced rains coincide with browner plants, the chances are that the climatic change causes the changes in the plants.
The results of the research, ‘A conceptual model for assessing rainfall and vegetation trends in sub-Saharan Africa from satellite data,’ were published in International Journal of Climatology. The research was supported by the EU-FP7 funded Geoland-2 project.
Source: University of Leicester