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Remote Sensing of Humid to Arid Gradients in Asia: A Review
Maxim Shoshany
Prof.
Technion - Israel Institute of Technology,
Israel
Email: maximsh@tx.technion.ac.il
Global warming, desertification and anthropogenic disturbances to the natural ecosystems are the primary reasons for the formation and shift of threshold zones between Humid and Arid regions. Good Governance should promote identification of threshold zones, decreasing disturbance levels in these sensitive areas and their natural recovery. Alternatively, aggravated desertification will occur with significant reduction of their natural resilience and of the long-term sustainability of rural communities of these regions. However, identifying threshold zones is a very challenging task due to the inherent spatial heterogeneity of regions of transition: their temporal variability, frequent changes in land-use mosaics, and superimposition effects from past climatic and land-use conditions. Soil and vegetation patterns are good indicators of the processes taking place at the humid to arid transition zones and remote sensing is a primary source for monitoring them. Various interpretation methods were developed for this purpose ranging from simple empirical modeling of vegetation cover- reflectance relationships, through biophysical modeling of radar backscattering to remote sensing studies integrating extensive field assessments of vegetation and soil properties. Results obtained from remote sensing research in the Middle East, Central and southern Asia suggest that phenomenological knowledge is important for improving the significance of remote sensing data in revealing sensitive transition zones.
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