Namib Desert

Dune 7, the highest sand dune in the world (ca. 383 m.), in the Namib Desert, Namibia.

The dune sea of the Namib Desert. Note how the crests of the dunes are aligned in a marked northwest-southeast orientation. These crests form transverse to the formative wind (i.e. crosswise). The dunes act as obstacles, and obstacles cause winds to be deflected significantly to the right, in the southern hemisphere—in effect reorienting the southerly wind as a southwesterly wind.

Sunset at the Namib Rand Nature Reserve, Namibia.

The Namib Desert is a desert in Namibia which forms part of the Namib-Naukluft National Park, one of Africa's largest. The name "Namib" is from a word in the Nama language that means "immense." The desert occupies an area of around 1 E10 m²|50 000 km², stretching some 1,000 miles (1,600 km) along the Atlantic Ocean coast of Namibia, which is named after this desert. Its east-west width varies from 30 to 100 miles (50-160 km). The Namib Desert also reaches into southwest Angola.

The area is considered to be the oldest desert in the world, having endured arid or semi-arid conditions for at least eighty million years. Its aridity is caused by the descent of dry air cooled by the cold Benguela current along the coast. It has less than 10 mm (0.4 inches) of rain annually and is almost completely barren.

A number of unusual species of plants and animals are found only in this desert. One of these is Welwitschia mirabilis, a shrublike plant but grows just two long, strap-shaped leaves continuously throughout its lifetime. These leaves may be several meters long, gnarled and twisted from the desert winds. The taproot of the plant develops into a flat, concave disc with age. Welwitschia is notable for its survival in the extremely arid conditions in the Namib, sometimes deriving moisture from the coastal sea fogs. Cold water meeting the hot desert is what creates the fog along the coast. These fogs and the fresh water they contain are the life essence of the Namib. Moisture condenses on desert grasses and on the bodies of smaller creatures. These sparse drops of dew are what sustain many of these animals.Devoid of rivers, the desert offers only a sparse selection of muddy water holes, but the animals of the Namib are not particular. In the first hours of the day, before the heat sears the land, gemsbok, ostriches, sand grouse, vultures, and wart hogs congregate at these oases to drink.

Also known as the oryx, the gemsbok has the lightest colored coat of any long-horned antelope subspecies and ventures the deepest into the desert. The gemsbok can withstand the intense heat of the Namib because of its intricate system of blood vessels and nasal passages, which cool blood before it reaches the brain. Gemsbok obtain water by digging for it underground, drinking from watering holes, and feeding in the early morning on plants with high moisture content. Access to watering holes is determined by sex and physical condition, males evicting females and the strong evicting the weak. If no water is available, gemsbok will let their body temperature rise before they begin to sweat, and will also raise their respiration rate from 20 to 120 pants per minute. At night, in order to sustain their body temperature without losing any water, they will breath slowly and deeply. As result of the gemsbok's numerous adaptations, it is able to tolerate high temperatures and go days without water.

Heavy fishing off the Namib coast has led to a decline the fish population, and consequently, a drop in the region's seabird population. Still, at least 150 bird species persist in the area, including flamingos, pelicans, and terns. Jackass penguins, found nowhere else on Earth, inhabit several islands just off the Namib coast. Of the many bird species in Namib, perhaps none has been as dramatically detrimented by commerical fishing as the jackass penguin. The population has dropped nearly 90% since 1930, when it numbered over 1,000,000.

Although the desert is largely unpopulated and inaccessible, there are year-round settlements at Sesriem, close to Sossusvlei and a huge group of sand dunes, which at up to 340 meters high are the tallest sand dunes in the world. The complexity and regularity of dune patterns in its dune sea have attracted the attention of geologists for decades; however, they remain poorly understood.

Sossusvlei is a great dry clay marsh (“vlei”). In some years, during the rainy season the waters of the Tsauchab River arrived around Sossusvlei, forming evocative pools of water at the feet of dunes. “Sossus” means “blind river” in the Nama language, so the literary translation of the word Sossusvlei is “marsh of the blind river”, that is “marsh of the river that does not have a mouth towards the sea”.

The interaction between the water-laden air coming from the sea via southerly winds, some of the strongest of any coastal desert, and the dry air of the desert causes immense fogs and strong currents in which sailors easily lose their way. Along with the Skeleton Coast farther north, the area is notorious as the site of many shipwrecks. Some of these wrecked ships can be found as much as 50 meters inland, as the desert is slowly creeping westward into the sea, reclaiming land over a period of many years.

The Namib is an important location for the mining of tungsten, salt, and diamonds.

Access is via light aircraft from Windhoek (the capital of Namibia, about 480 km east of the center of the desert), Swakopmund and Walvis Bay at the north end of the desert, or overland on gravel roads.

References

ISBN links support NWE through referral fees

• National Geographic, January 1992, pp. 54-85.
• Dune Patterns, Namib Desert, Namibia. NASA Earth Observatory. Retrieved 2006-05-05.
• Namib Naukluft Park photo gallery
• Namib Desert photo gallery
• [1], observed March 18, 2007.

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Its eastern border in the north and center is the foot of the Great Western Escarpment, atop which more humid lands prevail; but in the south, a gradual transition merges the Namib with the Kalahari and Karoo Deserts of the interior.

Climate: Climatically, the Namib is a contradictory area: It is almost rainless, yet its air is normally at or near the saturation point, and fog is very common. Temperatures in the coastal area are mild at all seasons, ranging between a maximum of 67 degrees Fahrenheit and a minimum of 58 degrees Fahrenheit in the warm season (December) and between 57 degrees Fahrenheit and 46 degrees Fahrenheit in the cool (July). Inland, more continental conditions prevail, with summer temperatures reaching the 80s each day and dropping into the low 40s on the average winter night on the coast, humidity is at 100 percent for 19 hours per day in summer and for 11 hours in winter. At the inner edge of the desert, the air is much drier, fog is virtually unknown, and the humidity seldom exceeds 50 percent. This is nevertheless fairly high for a desert region. Violent weather is practically unknown. rare thunderstorms bring the precipitation, which averages less than 2 inches annually inland, and about one-half inch at the coast. Strong winds blow a few days a year from the interior, bringing heat and discomfort to the coast. But storms such as characterize mid-latitude areas are totally unknown.

Landforms: The Namib is characterized by several distinct types of landforms: A vast sand sea, monotonously flat plains of gravel and bedrock, mountains of bare rock, and areas with surfaces fretted into strange sandblasted forms. Most of the desert consists of a broad platform, eroded into bedrock of monotonous flatness and rising in a very gradual slope from the coastline to an elevation of some 3,000 feet at the foot of the escarpment. South of the Tropic (of Capricorn), much of this platform is veneered with sand, in the form of sheets, waves, and dunes, the latter sometimes exceeding 800 feet, making them the highest sand dunes in the world. In the southern and central portions, mountains rise about the smooth platform only as isolated individuals and short chains. Most of the mountains are rugged, steep sloped, and almost soilless.

Vegetation : In general, the Namib is a barren waste, with very sparse vegetation. Large areas, notably the gravel flats, the bedrock platform, and the dunes, are almost totally barren. In the zone of heaviest fog near the coast, especially in the south, low succulent bushes grow sporadically. Along the eastern border, a thin to moderate cover of annual grasses appears in most years, supporting for a time a variety of antelopes, zebra, ostrich, and their attendant predators.

Water Supply : Potable water is found only as sub-flow beneath streambeds chiefly of the larger streams that rise in the rainier plateau east of the escarpment. In some cases, dissolved salts render the water unpleasant. In other cases, such as the Kuiseb and the Koichab, which supply Walvis Bay and Luderitz, the quality is good to excellent.

Settlements : Walvis Bay has the only harbor on the Namibian coast accessible to deep-water vessels with large freighters and tankers able to come alongside the modern, efficient wharves. Fishing factories line the shore of the bay, each with its own wharf. As the only deep-water railhead in the country, Walvis Bay serves as the principal entry port for the interior. In addition to fish products, exports are chiefly minerals, wool, hides, and pelts destined for all parts of the world. Imports consist chiefly of manufactured goods, petroleum, and foodstuffs. The total population of the town is about 21,000. The water supply to the town is via a pipeline from the Kuiseb River, 23 miles to the southeast, where it is tapped from wells into the underflow of the river. Luderitz is a small-scale replica of Walvis Bay, except that its harbor is not suitable for deep-water vessels. The town's chief role is as the base for the rock lobster or crayfish industry. As a cargo port, its role is minor; its hinterland is poor and is serviced by a rail line and a single graded road. Its population is about 10,000. Its water supply also is from an underflow well mining (of the Koichab River through a 67-mile pipeline across the Namib.

Mining : Diamonds constitute by far the most important mineral product in the territory. The diamonds are alluvial, being found in beds of gravel, usually under a considerable overburden of sterile materials. The large-scale operation of recovery of diamonds is now under one corporation: the Consolidated Diamond Mines (CDM). Because of the high value and light weight of the product and the resultant ease of theft (combined with the difficulty of rescue operations for retrieving "poachers" stranded in this extremely arid region), the entire diamond bearing area and much of its surroundings has been proclaimed a Prohibited Area (Sperrgebiet), totally closed to public entry at all times. The CDM company town of Oranjemund, at the mouth of the Orange River, is the center of diamond mining operations. It is a highly developed, progressive, modern community, with a good water supply from wells near the river and with gardens supplying fresh produce. Offshore dredging operations for the recovery of diamonds from the sea bed have been carried on.

Other minerals mined in the Namib include zinc (Rosh Pinah mine), tin and wolfram (at Uis and Brandberg Wes). Oil prospecting has been carried out in recent years, but without success.

Recreation and Tourism : Since the time of German Southwest Africa, the coastal towns of the Namib have always had an attraction to the few and hardy. With the cooler summer climate, the fishing, the relative barrenness of the area, and its historic Germanic flavor have all been attractions for visitors.