Land surface remote sensing : environment and risks

Regions with dry climates cover a large part of the world’s landmass (more than 40%). Collectively known by the English term "drylands", they encompass a wide range of ecosystems, including the American "deserts" of California, Nevada and Mexico ; the vast steppes of Central Asia and North Africa ; the Sahelian savannah and real deserts such as the Sahara in Africa or the Gobi in China.