|The major part of North-West Africa consists of deserts where dominant dryness and high solar radiation prohibits any vegetation from growing, making human presence and any economic activity related to traditional agriculture or grazing hardly sustainable.
Aerial picture: Saharan Coastline 100 miles North of Tarfaya
The combination of high daily temperature differences and a lengthy erosion process have significantly affected the morphology of the region. The soil structure has been eroded for thousands of years. Today over 90 % of the Sahara desert is made out of large flat rocky surfaces or plateaus called Hammada’s. These inert stony areas made of broken bare rock structures are actually characterized by a very small surface roughness to wind.
The sand dunes common to our imagination represent actually only about 5 % of the entire surface of the Sahara desert.
The junction of the Sahara desert with the Atlantic Ocean creates a zone of global energy exchange were the climate is dominated by steady winds spreading inland over a long distance. The large Atlantic desert coastline from Morocco to Senegal is about 2000 kilometers long. It represents one of the largest and windiest areas on earth.
Because of the extremely harsh climatic conditions, the population densities in these areas are in the order of less than 1 hab/km² concentrated around water supply sources. These constitute the main attraction poles, that are shaping local communities into a few cities spread throughout this vast region.