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Land-cover changes in sub-saharan Africa (1982-1991) : Application of a change index based on remotely sensed surface temperature and vegetation indices at a continental scale
Author
Lambin, Eric F
Ehrlich, Daniele
Publisher
Remote Sensing of Environment
Publication Year
1997
Body

There is an increasing need for data on land-cover changes at broad spatial .scales. In this study, a remote sensing-based technique for land-cover-change analysis was applied to the African continent for the last decade. Ten years of daily, continental-.scale satellite remote sensing data (front the National Oceanic and Atmospheric Administration's advanced very-high resolution radiometer) were analyzed. Deviations in. the seasonal trajectory of the land surface--characterized by its brightness temperature and a vegetation index--were interpreted in terms of land-cover change on a yearly basis, from 1982 to 1991. Land-cover-change magnitudes were measured and mapped for every year. The major categories of seasonal patterns of changes were identified. Multiyear patterns of change also were categorized, and all areas affected by a continuous decrease and gain in vegetation cover over the decade were snapped. Results were related to published high-resolution remote sensing-based studies, rainfall data, and other evidence of land-cover changes. This study's results demonstrate that inte-rannual land-cover changes in Africa mostly involve erratic variations in land-corer conditions due to interannual climatic variability and temporary nwdifncations in seasonality. Continuous, unidirectional change processes (decrease or gain in vegetation cover) affected less than 4% of sub-Saharan Africa during the study period. Althongh such linear changes are just a fraction of the total land-cover changes detected, their effect on ecosystems and sustainability of livelihood might be significant. In the semiarid regions, temporary modification of the biophysical attributes of the surface driven by variations in rainfall is the dominant process. Future work will focus on finer-scale interpretation and validations of patterns of changes.

Language
English
Resource Type
Text
Document Type
Journal Issue/Article
Journal Volume
61
Journal Number
2
Journal Pages
181-200
Collection
Southern Africa Collection
Journal Name
Remote Sensing of Environment
Keywords
remote sensing
rainfall
climate
ecosystem dynamics
Africa