RSS-FeedNamib
The Namib is a coastal desert with a length of 2,000 km and width of 30 to 100 km. The surface covers 270,000 km². In the north, the Namib reaches up to Angola. In the south, it is bordered by the Oranje river, in the west by the Atlantic Ocean and in the east by the large edge stage. From here, the Namib drops 800 m down to sea level.
Its drought is due to the location on both sides of the southern tropics. The lack of rain is aggravated by the direct neighbourhood to a cold ocean current. At the Tropic of Capricorn, the Namib extends only 30 to 100 km from the Atlantic Ocean into the land mass of the African continent. The reasons for this are enormous ocean currents that affect the atmospheric circulation in southern Africa. They prevent a continuous desert strip from the Atlantic Ocean to the Indian Ocean. Towards the Indian Ocean, the warm Mozambique stream provides sufficient precipitation.
An ocean current coming from the Antarctic, the Benguela stream, increases the drought at the Atlantic coast. Its cold upwind waters substantially cool down the air masses over the sea. If they meet the mainland, an inversion between the warm and dry air masses over the mainland and the cool and damp sea air which is under it, happens, which makes the formation of productive precipitation impossible. Near the coast, fog clouds are formed that are blown by strong winds from sea towards the mainland. The fog often persists all day, but it only extends up to 30 km into the interior of the country.
The extension of the fog is the criterion that lets us differentiate between Coastal Namib and Internal Namib. The more offshore the area, the lower the precipitation.
The fog over the Coastal Namib corresponds to an annual precipitation amount between 40 to 50 mm and thereby forms the basis of life for an adapted flora. Thanks to the high plankton and oxygen content of the Benguela stream, that makes the territorial waters the fish-richest of the earth, the coast of the Namib is a habitat for millions of sea-birds and seals.
This image is in the public domain because it is a screenshot from NASA’s globe software World Wind using Blue Marble, Landsat or USGS layer, all of which are in public domain.
Photo: Carola Böhringer
Photo: Carola Böhringer
In the east, a 30 to 50 km broad strip of the Coastal Namib neighbours the Internal Namib. It is located at an altitude between 400 and 500 m and is therefore outside of the range of the coastal fog. High temperatures and low humidity prevail.
In the Namib submontane, at the edge of the large stage, extensive cattle breeding is possible thanks to up to 100 mm of precipitation per year. However, the vegetation is so sparse that a pastureland of 30 hectares is needed per cow.
The Namib is often called the oldest desert of the earth. It seems that there has never been a change between wet and dry phases since the Benguela stream has been flowing for millions of years causing low precipitation. Due to the age-old continuous desert conditions, the fauna of the Namib is highly specialized.