Sudan is located in Northeast Africa. It is bordered by Egypt to the north, the Red Sea to the northeast, Eritrea and Ethiopia to the east, South Sudan to the south, the Central African Republic to the southwest, Chad to the west and Libya to the northwest. Covering , it is the third largest country in Africa, after Algeria and the Democratic Republic of the Congo. It was the largest country on the continent until South Sudan split off from it in 2011.
Geographical regions
Northern Sudan – lying between the Egyptian border and Sennar – has two distinct parts, the desert and the Nile Valley. Though published in 2015, this work covers events in the whole of Sudan (including present-day South Sudan) until the 2011 secession of South Sudan. To the east of the Nile is the Nubian Desert and to the west, the Libyan Desert. Both are stony, with sandy dunes drifting over the landscape. There is virtually no rainfall in these deserts. Water in the Libyan desert is limited to a few small watering holes, such as Bir an Natrun, where the water table reaches the surface to form wells that provide water for nomads, caravans, and administrative patrols, although insufficient to support an oasis and inadequate to provide for a settled population. The Nubian Desert has no oases. Flowing through the desert is the Nile Valley, whose alluvial strip of habitable land is no more than two kilometers wide and whose productivity depends on the annual flood.
Sudan's western front encompasses the regions known as Darfur and Kurdufan that comprise . Traditionally, this has been regarded as a single regional unit despite the physical differences. The dominant feature throughout this immense area is the absence of perennial streams; thus, people and animals must remain within reach of permanent wells. Consequently, the population is sparse and unevenly distributed. Western Darfur is an undulating plain dominated by the volcanic massif of Jabal Marrah towering above the Sudanic plain; the drainage from Jabal Marrah onto the plain can support a settled population and a variety of wildlife (see East Saharan montane xeric woodlands). Western Darfur stands in contrast to northern and eastern Darfur, which are semi-deserts with little water either from the intermittent streams known as wadis or from wells that normally go dry during the winter months. Northwest of Darfur and continuing into Chad lies the unusual region called the jizzu, where sporadic winter rains generated from the Mediterranean frequently provide excellent grazing into January or even February. The southern region of western Sudan is known as the qoz, a land of sand dunes that in the rainy season is characterized by a rolling mantle of grass and has more reliable sources of water with its bore holes and hafri (sing., hafr) than the north does. The highest peak in Sudan – Deriba caldera, of the Marrah Mountains – is in this region. A unique feature of western Sudan is the Nuba mountain range of southeast Kurdufan in the center of the country, a conglomerate of isolated dome-shaped, sugarloaf hills that ascend steeply and abruptly from the great Sudanic plain. Many hills are isolated and extend only a few square kilometers, but there are several large hill masses with internal valleys that cut through the mountains high above the plain.
Sudan's third distinct region is the central clay plains that stretch eastward from the Nuba Mountains to the Ethiopian border, broken only by the Ingessana Hills, and from Khartoum in the north to the far reaches of southern Sudan. Between the Dindar and the Rahad rivers, a low ridge slopes down from the Ethiopian highlands contrasting the neighboring plains as do the occasional hills. The central clay plains provide the backbone of Sudan's economy because of the large amounts of settlements which are there due to the available water. In the heartland of the central clay plains lies the jazirah, (literally in Arabic "peninsula") the land between the Blue Nile and the White Nile where the great Gezira Scheme was developed. This project grows cotton for export and has historically produced more than half of Sudan's revenue and export earnings.
Northeast of the central clay plains lies eastern Sudan, which is divided between desert and semi-desert and includes the Butana, the Qash Delta, the Red Sea Hills, and the coastal plain. The Butana is an undulating land between Khartoum and Kassala that provides good grazing for cattle, sheep, and goats. East of the Butana is a geological formation known as the Qash Delta. Originally a depression, it has been filled with sand and silt brought down by the flash floods of the Qash River, creating a delta above the surrounding plain. Extending 100 kilometers north of Kassala, the whole area watered by the Qash is a rich grassland with bountiful cultivation long after the river has spent its waters on the surface of its delta. Trees and bushes provide grazing for the camels from the north, and the rich moist soil provides an abundance of food crops and cotton.
Northward beyond the Qash lie the Red Sea Hills. Dry, bleak, and cooler than the surrounding land, particularly in the heat of the Sudanese summer, they stretch northward into Egypt, a jumbled mass of hills where life is hard and unpredictable for the Beja inhabitants. Below the hills sprawls the coastal plain of the Red Sea, varying in width from about fifty-six kilometers in the south near Tawkar to about twenty-four kilometers near the Egyptian border. The coastal plain is dry and barren. It consists of rocks, and the seaward side is thick with coral reefs. Political geography
Sudan is divided into 18 states and one area with special administrative status. The states of Sudan are:
Khartoum North Kordofan Northern Kassala Blue Nile North Darfur South Darfur South Kordofan Gezira White Nile River Nile Red Sea Al Qadarif Sennar West Darfur Central Darfur East Darfur West Kordofan (disestablished in 2005; reestablished in 2013)
As a result of the Comprehensive Peace Agreement signed in 2005, the Abyei Area was given special administrative status and following the independence of South Sudan in 2011, is considered to be simultaneously part of both the Republic of Sudan and the Republic of South Sudan, effectively a condominium. Area and boundaries Area Total: country rank in the world: 15th Land: Water:
Area comparative Australia comparative: slightly larger than Queensland Canada comparative: slightly smaller than Nunavut United States comparative: approximately times the size of Alaska
Land boundaries Total: . Border countries: Central African Republic () Chad () Egypt () Eritrea () Ethiopia () Libya () South Sudan (). Islands Sudan has islands located in the Nile and other rivers, in lakes and reservoirs and in the Red Sea.
River Islands Tuti Island, Aba Island, Badien Island, Sai Island.
Red Sea Islands Dungunab Bay Mukawwar Island (Jazirat Magarsam), Jazirat Mayteb, Jazirat Bayer, Juzur Telat.
Suakin Archipelago Talla Talla, Kebir Island, Taimashiya Island, Dar Ah Teras, Andi Seli, Masamarhu Island, Abu Isa Island, Dahrat ed Dak Hillat Island, Ed Dom esh Sheikh Island, Darrakah, Miyum, Zahrat Ghab, Jazirat Zahrat Abid, Gazirat Iri, Sayl Bahr, Gazirat Abid, Gazirat Wahman, Jaza'ir Amarat, Quban Island, Bakiyai Islands, Gazair Hayyis Wa Karai, Saqir Island, Sumar Island, Long Island, Gap Island, Two Islands.
Lake and Reservoir Islands Roseires Reservoir Jazirat Maqanza, Jazirat Abu Ushar, Jazirat Muluwwa. Jebel Aulia Reservoir Gazerat Jene't. Er Rahad Lake Four small islands and several islets.
Climate
Although Sudan lies within the tropics, the climate ranges from hyper-arid in the north to tropical wet-and-dry in the far southwest. Though published in 2015, this work covers events in the whole of Sudan (including present-day South Sudan) until the 2011 secession of South Sudan. Temperatures do not vary greatly with the season at any location; the most significant climatic variables are rainfall and the length of the wet and dry seasons. Variations in the length of the wet and dry seasons depend on which of two air flows predominates: dry northern winds from the Sahara and the Arabian Peninsula or moist southwesterly winds from the Congo River basin and southeasterly winds from the Indian Ocean.
From January to March, the country is under the influence of dry northeasterlies. There is minimal rainfall countrywide except for a small area in northwestern Sudan where the winds have passed over the Mediterranean bringing occasional light rains. By early April, the moist southwesterlies have reached southern Sudan, bringing heavy rains and thunderstorms. By July, the moist air has reached Khartoum, and in August it extends to its usual northern limits around Abu Hamad, sometimes the humid air reaches as far as the Egyptian border. The flow becomes weaker as it spreads north. In September the dry northeasterlies begin to strengthen and to push south and by the end of December they cover the entire country. Khartoum has a three-month rainy season (July–September) with an annual average rainfall of ; Atbarah receives showers in August that produce an annual average of only .
In some years, the arrival of the southwesterlies and their rain in central Sudan can be delayed, or they may not come at all. When that happens, drought and famine follow. The decades of the 1970s and 1980s saw the southwesterlies frequently fail, with disastrous results for the Sudanese people and economy.
Temperatures are highest at the end of the dry season when cloudless skies and dry air allow them to soar. The far south, however, with only a short dry season, has uniformly high temperatures throughout the year. In Khartoum, the warmest months are May and June, when average highs are and temperatures can reach . Northern Sudan, with its short rainy season, has very high daytime temperatures year round, except for winter months in the northwest where there is some precipitation in January and February. Conditions in highland areas are generally cooler, and the hot daytime temperatures during the dry season throughout central and northern Sudan fall rapidly after sunset. Lows in Khartoum average in January and have dropped as low as after the passing of a cool front in winter.
The haboob, a violent dust storm, can occur in central Sudan when the moist southwesterly flow first arrives (May through July). The moist, unstable air forms thunderstorms in the heat of the afternoon. The initial downflow of air from an approaching storm produces a huge yellow/red wall of sand and clay that can temporarily reduce visibility to zero.
Desert regions in central and northern Sudan are among the driest and the sunniest places on Earth: the sunshine duration is always uninterrupted year-round and rise to above 4,000 hours or about 91% of the time with the sky being cloudless all the time. Areas around Wadi Halfa and along the Egyptian border can easily pass many years or many decades without seeing any rainfall at all. They are also among the hottest places during their summertime and their "wintertime": averages high temperatures routinely exceed 40 °C (104 °F) for four to nearly six months a year to reach a maximum peak of about 45 °C (113 °F) in some places and averages high temperature remain above 24 °C (75.2 °F) in the northernmost region and above 30 °C (86 °F) in places such as Atbara or Meroe.
Hydrology