Mapping 30 Years of Land Cover & Fraction Cover Changes over the Sahel
Start of a better inventory of the vital drivers of environmental change
The scientific paper ‘Thirty Years of Land Cover and Fraction Cover Changes over the Sudano-Sahel Using Landsat Time Series’ has been published in Remote Sensing and is available online.
Through this paper, VITO Remote Sensing, Wageningen University, Ghent University, University of Copenhagen and KU Leuven present the methodology and historical high-resolution land cover maps for the Sahel Region.
In this study, 30 m resolution historically consistent land cover and cover fraction maps are provided over the Sudano-Sahel for the period 1986–2015.
A good inventory of changes is needed to determine drivers and turning points within an ecosystem.
Niels Souverijns, VITO Remote Sensing
These land cover/cover fraction maps are achieved based on the Landsat archive preprocessed on Google Earth Engine and an adapted version of the random forest classification/regression model which was previously used to obtain the Copernicus Global Land Cover maps. Historical consistency is achieved using the hidden Markov model. Using these historical maps, a multitude of variability in the dynamic Sudano-Sahel region over the past 30 years is revealed. On the one hand, Sahel-wide cropland expansion and the re-greening of the Sahel is observed in the discrete land cover classification. On the other hand, subtle changes such as forest degradation are detected based on the cover fraction maps. Additionally, exploiting the 30 m spatial resolution, fine-scale changes, such as smallholder or subsistence farming, can be detected. The historical land cover/cover fraction maps presented in this study are made available via an open-access platform.