ARABIAN DESERT

The prominent escarpment of Mount Tuwayq in the Arabian Desert south of Riyadh, Saudi Arabia. great desert region occupying nearly all of the Arabian Peninsula in Southwest Asia, an area of about 900,000 square miles (2,330,000 square km). The Arabian Desert is bordered by the Syrian Desert to the north; the Persian Gulf, Gulf of Oman, and Arabian Sea to the east; the Arabian Sea and Gulf of Aden to the south; and the Red Sea to the west. A large part of the desert lies within Saudi Arabia; it also extends into Jordan, Iraq, Kuwait, Qatar, the United Arab Emirates, Oman, and Yemen. Two major regions comprise the desert: the ancient Arabian Platform (or Afro-Arabian Shield) of igneous and metamorphic rocks in the west, and the younger sedimentary rocks that dip gently away from the shield toward the Persian Gulf basin to the east. Mountainous highlands rise in the northwest, southwest, and southeast corners of the desert; steep cliffs and canyons descend from the highlands into adjacent seas to the south and west. To the north and east, elevations decrease more gradually to the moderate relief of the interior plateaus and broad plains or steppes. A number of lesser highland ranges have been uncovered by erosion in the interior. Sand covers at least a third of the Arabian Desert, occurring as dunes or ridges of varying size and complexity or as a thin film on surfaces of low relief. The two largest sand bodies are an-Nafud in the northwest and the Rub 'al-Khali in the southeast. Between them are two almost parallel arcs of more or less continuous dunes, separated by the Tuwayq Mountains. Twice a year shamal winds blow at velocities averaging 30 miles per hour (50 km per hour) from the north and northwest for 30 to 50 days, transporting huge loads of sand and dust and altering the shapes of sand dunes. Summer heat in the desert is intense, with daytime highs reaching 129 F (54 C). In the interior the heat is dry and tolerable, but coastal regions and some highlands suffer from high summer humidity. Rainfall averages less than 4 inches (100 mm) a year but can range from 0 to 20 inches (500 mm). Most drainage channels in the desert are either dry or intermittent, the latter flowing only when rains are heavy. Two systems flow perennially in the regionthe Tigris-Euphrates river system in the northeast and the Wadi Hajr in the southern Hadhramaut (Hadramawt) region of Yemen. Plants of the Arabian Desert are structurally adapted to dry or saline conditions. Humans have inhabited the desert since early Pleistocene times (the Pleistocene lasting from about 1.6 million to 10,000 years ago). The nomadic Bedouin adapted to desert life by migrating seasonally with their herds of camels, Arabian horses, and sheep into the desert during the rainy winter season and moving back toward the cultivated lands in the dry summer months. Date palms are grown in many oases, the dates providing food for humans and livestock, and the palm supplying wood for building. Many fruits, grains, and vegetables, such as rice, alfalfa, henna, citrus, melons, onions, tomatoes, barley, and wheat, are also grown in the oases, andin the higher regionspeaches, grapes, and prickly pears. The Arabian people, Muslim from the 7th century AD, remained largely unaffected by Western cultural influences until the discovery of petroleum in 1936. Their desert, once crossed only by camel trails, is now laced by networks of roads; about four-fifths of the territory is accessible by motor vehicles. The Arabian Desert. great desert region occupying almost the entire Arabian Peninsula. Covering an area of about 900,000 square miles (2,330,000 square kilometres), it is bordered on the north by the Syrian Desert, on the northeast and east by the Persian Gulf and the Gulf of Oman, on the southeast and south by the Arabian Sea and the Gulf of Aden, and on the west by the Red Sea. A large part of the Arabian Desert lies within the modern kingdom of Saudi Arabia. Yemen, on the coast of the Gulf of Aden and the Red Sea, borders the desert to the southwest. Oman, bulging out into the Gulf of Oman, borders the desert at its eastern extremity. The sheikhdoms of the United Arab Emirates (former Trucial States) and Qatar rim the region to the northeast, stretching along the southern coast of the Persian Gulf. The emirate of Kuwait abuts the northern Persian Gulf between Saudi Arabia and Iraq; a Neutral Zonediamond-shapedlying to the west of Kuwait is shared by Saudi Arabia and Iraq. In the northwest the desert extends into Jordan. Seen from the air, the Arabian Desert appears as a vast expanse of light sand-coloured terrain with an occasional indistinct line of escarpments or mountain ranges, black lava flows, or reddish systems of desert dunes stretching to the horizon. Camel trails crisscross the surface between watering places. On the ground, features become distinctly individual and the relief seems more prominent. Vegetation at first seems nonexistent, but to the discerning eye can be seen as a minor fuzz on the surface, or as bits of green where shrubs strive to survive. There is almost always a breeze, which changes seasonally to winds of gale force. Cold or hot, these air currents chill the body or roast it. The Sun and Moon are bright in clear skies, although dust and humidity may cut visibility with little warning. Additional reading Descriptive surveys of the Arabian Desert include Wilfred Thesiger, Arabian Sands (1959, reissued 1983), a modern classic; Colbert C. Held, Middle East Patterns: Places, Peoples, and Politics (1989), with a general geography of Southwest Asia; and accounts of important travels in the region, such as Charles M. Doughty, Travels in Arabia Deserta, new ed., 2 vol. (1936, reprinted 1979); T.E. Lawrence, Seven Pillars of Wisdom (1935, reissued 1988); and H.St.J.B. Philby, The Empty Quarter: Being a Description of the Great South Desert of Arabia Known as Rub' al Khali (1936, reprinted 1986), and Arabian Highlands (1952, reprinted 1976). Two valuable works on the flora and fauna are Betty A. Lipscombe Vincett, Wild Flowers of Central Saudi Arabia (1977); and Wilhelm Bttiker (ed.), The Wildlife of Arabia (1981). A.R. Ansary, Qaryat al-Fau: A Portrait of Pre-Islamic Civilization in Saudi Arabia (1982), discusses early patterns of settlement in the desert. Norman Anderson et al., The Kingdom of Saudi Arabia, 8th ed. (1990), contains a number of useful studies. H.R.P. Dickson, The Arab of the Desert, 3rd ed., rev. by Robert Wilson and Zahra Freeth (1983), discusses Bedouin culture and custom prior to 1940. The impact of modernization on the peoples of the desert areas is addressed by Donald Powell Cole, Nomads of the Nomads: The Al Murrah Bedouin of the Empty Quarter (1975); Motoko Katakura, Bedouin Village: A Study of a Saudi Arabian People in Transition (1977); and Soraya Altorki and Donald Powell Cole, Arabian Oasis City: The Transformation of 'Unayzah (1989). William L. Ochsenwald