Part 1 of this publication presents scientific concepts of land health surveillance and the methods and analytical approaches that are used to make surveillance operational. Part 2 presents a regional application of land health surveillance with a synoptic screening study of land degradation in the Sahel using historical changes in vegetation growth and rainfall patterns, based on remote sensing.
The atlas provides a pictorial overview of the application of land degradation surveillance a science-based approach to land health monitoring and assessment. Systematic sampling and observation of ground conditions are combined with new technology for rapid soil characterization and with fine to moderate resolution satellite imagery to provide powerful inference about soil, vegetation and socioeconomic conditions at local to regional scales.
Wind erosion is a critical environmental problem that threatens mainly the arid and semi-arid regions of our planet. Usually this problem is associated with desertification, poverty and other environmental and socioeconomic problems. Wind erosion causes the loss of fertile topsoil, and has a negative effect on agricultural production and on human health. When conditions favorable for wind erosion are present, the process can cause large scale environmental disasters like the Dust Bowl in the USA in the 1930s.
Land degradation is a global issue on a par with climate change and loss of biodiversity, but its extent and severity are only roughly known and there is little detail on the immediate processes – let alone the drivers. Earth-observation methods enable monitoring of land resources in a consistent, physical way and on global scale by making use of vegetation activity and/or cover as proxies. A well-known spectral proxy is the normalized difference vegetation index (NDVI), which is available in high temporal resolution time series since the early 1980s.
Water erosion is the most important degradation process of the 10 degradation processes distinguished by the European Union. The impact of rain drops on the soil surface causes splash of soil particles
