The Nile is a major north-flowing river in Africa, generally regarded as the longest river in the world.
The Nile has two major tributaries, the White Nile and Blue Nile, the latter being the source of most of the Nile's water and fertile soil, but the former being the longer of the two. The White Nile rises in the Great Lakes region of central Africa, with the most distant source in southern Rwanda at 2°16′55.92″S 29°19′52.32″E, and flows north from there through Tanzania, Lake Victoria, Uganda and southern Sudan, while the Blue Nile starts at Lake Tana in Ethiopia at 12°2′8.8″N 37°15′53.11″E, flowing into Sudan from the southeast. The two rivers meet near the Sudanese capital of Khartoum.
The northern section of the river flows almost entirely through desert, from Sudan into Egypt, a country whose civilization has depended on the river since ancient times. Most of the population and cities of Egypt lie along those parts of the Nile valley north of Aswan, and nearly all the cultural and historical sites of Ancient Egypt are found along the banks of the river. The Nile ends in a large delta that empties into the Mediterranean Sea.
The source of the Nile is sometimes considered to be Lake Victoria, but the lake itself has feeder rivers of considerable size. The most distant stream—and thus the ultimate source of the Nile—emerges from Nyungwe Forest in Rwanda, via the Rukarara, Mwogo, Nyabarongo and Kagera rivers, before flowing into Lake Victoria in Tanzania near the town of Bukoba.
The Nile leaves Lake Victoria at Ripon Falls near Jinja, Uganda, as the Victoria Nile. It flows for approximately 500 kilometres (300 mi) farther, through Lake Kyoga, until it reaches Lake Albert. After leaving Lake Albert, the river is known as the Albert Nile. It then flows into Sudan, where it is known as the Bahr al Jabal . The Bahr al Ghazal, itself 716 kilometres (445 mi) long, joins the Bahr al Jabal at a small lagoon called Lake No, after which the Nile becomes known as the Bahr al Abyad, or the White Nile, from the whitish clay suspended in its waters. When the Nile flooded it left a rich silty deposit which fertilised the soil. The Nile no longer floods annually since the completion of the Aswan Dam in 1970. From Lake No, the river flows to Khartoum. An anabranch river, the Bahr el Zeraf, flows out of the Nile's Bahr al Jabal section and rejoins the White Nile.
The term "White Nile" is used in both a general sense, referring to the entire river above Khartoum, and in a limited sense, describing the section between Lake No and Khartoum.
The flow rate of the Albert Nile at Mongalla is almost constant throughout the year and averages 1,048 m3/s (37,000 cu ft/s). After Mongalla, the Nile is known as the Bahr El Jebel, which enters the enormous swamps of the Sudd region of Sudan. More than half of the Nile's water is lost in this swamp to evaporation and transpiration. The average flow rate in the Bahr El Jebel at the tails of the swamps is about 510 m3/s (18,000 cu ft/s). From here it soon meets with the Sobat River and forms the White Nile.
The Bahr al Ghazal and the Sobat River are the two most important tributaries of the White Nile in terms of drainage area and discharge. The Bahr al Ghazal's drainage basin is the largest of any of the Nile's sub-basins, measuring 520,000 square kilometres (200,000 sq mi) in size, but it contributes a relatively small amount of water, about 2 m3/s (71 cu ft/s) annually, due to tremendous volumes of water being lost in the Sudd wetlands. The Sobat River, which joins the Nile a short distance below Lake No, drains about half as much land, 225,000 km2 (86,900 sq mi), but contributes 412 cubic metres per second (14,500 cu ft/s) annually to the Nile.[4] When in flood the Sobat carries a large amount of sediment, adding greatly to the White Nile's color.
The average flow of the White Nile at Malakal, just below the Sobat River, is 924 m3/s (32,600 cu ft/s); the peak flow is approximately 1,218 m3/s (43,000 cu ft/s) in early March and minimum flow is about 609 m3/s (21,500 cu ft/s) in late August. This fluctuation is due the substantial variation in the flow of the Sobat, which has a minimum flow of about 99 m3/s (3,500 cu ft/s) in August and a peak flow of over 680 m3/s (24,000 cu ft/s) in early March. During the dry season (January to June) the White Nile contributes between 70% and 90% of the total discharge from the Nile.
The Blue Nile to Ethiopians springs from Lake Tana in the Ethiopian Highlands. The Blue Nile flows about 1,400 kilometres (870 mi) to Khartoum, where the Blue Nile and White Nile join to form the Nile. 90% of the water and 96% of the transported sediment carried by the Nile originates in Ethiopia, with 59% of the water from the Blue Nile (the rest being from the Tekezé, Atbarah, Sobat, and small tributaries). The erosion and transportation of silt only occurs during the Ethiopian rainy season in the summer, however, when rainfall is especially high on the Ethiopian Plateau; the rest of the year, the great rivers draining Ethiopia into the Nile (Sobat, Blue Nile, Tekezé, and Atbarah) have a weaker flow.
The Blue Nile contributes approximately 80-90% of the Nile River discharge. The flow of the Blue Nile varies considerably over its yearly cycle and is the main contribution to the large natural variation of the Nile flow. During the wet season the peak flow of the Blue Nile will often exceed 5,663 m3/s (200,000 cu ft/s) in late August. During the dry season the natural discharge of the Blue Nile can be as low as 113 m3/s (4,000 cu ft/s), although upstream dams regulate the flow of the river.
Before the placement of dams on the river the yearly discharge varied by a factor of 15 at Aswan. Peak flows of over 8,212 m3/s (290,000 cu ft/s) would occur during late August and early September and minimum flows of about 552 m3/s (19,500 cu ft/s) would occur during late April and early May.
Thursday, March 25, 2010
Wednesday, March 24, 2010
Teneriffe Island
Tenerife, a Spanish island, is the largest of the seven Canary Islands in the Atlantic Ocean off the coast of Africa. Tenerife has an area of 2034.38 square kilometers, and 899,833 inhabitants. It is the most populated island of the Canary Islands and Spain. About 43% of the population of the Canary Islands housing on this island, this is almost half the total population of the archipelago. About five million tourists visit Tenerife each year, which is also one of the busiest Spain resorts and the first of Canary Islands. Tenerife also has one of the world's largest carnivals, and the Carnival of Santa Cruz de Tenerife now aspires to become a World Heritage Site. The island's capital contains the architectural symbol of the Canary Islands, the modern Auditorio de Tenerife. Tenerife is the only Spanish island that has two airports and two ports .
Santa Cruz de Tenerife is the capital of the island and the seat of the island council . The city is capital of the autonomous community of Canary Islands , sharing governmental institutions such as Presidency and ministries. Between the 1833 territorial division of Spain and 1927 Santa Cruz de Tenerife was the sole capital of the Canary Islands, until in 1927 a decree ordered that the capital of the Canary Islands be shared, as it remains as at present.
The island is home to the University of San Fernando de La Laguna, which was founded in 1792. The University of La Laguna is the oldest university in the Canaries. San Cristóbal de La Laguna is the second city of the island and the third one of the archipelago. The city of La Laguna was also capital of the Canary Islands until Santa Cruz replaced it in 1833.
Tenerife also has the highest elevation of Spain, a World Heritage Site that is the third largest volcano in the world from its base, El Teide.
Tenerife is a rugged and volcanic island sculpted by successive eruptions throughout its history. There are four historically recorded volcanic eruptions, none of which has led to casualties. The first occurred in 1704, when the Arafo, Fasnia and Siete Fuentes volcanoes erupted simultaneously. Two years later, in 1706, the greatest eruption occurred at Trevejo. This volcano produced great quantities of lava which buried the city and port of Garachico. The last eruption of the 18th century happened in 1798 at Cañadas de Teide, in Chahorra. Finally, and most recently, in 1909 the Chinyero volcano, in the municipality of Santiago del Teide, erupted.
The island is located between 28º and 29º N and the 16º and 17º meridian. It is situated north of the Tropic of Cancer, occupying a central position between the other Canary Islands of Gran Canaria, La Gomera and La Palma. The island is about 300 km (186 mi) from the African coast, and approximately 1,000 km from the Iberian Peninsula. Tenerife is the largest island of the Canary Islands archipelago, with a surface area of 2,034.38 km2 and the longest coastline amounting to 342 km.
In addition, the highest point, Mount Teide, with an elevation of 3,718 m above sea level is the highest point in all of Spain. It comprises about 200 small barren islets or large rocks including Roques de Anaga, Roque de Garachico, and Fasnia adding a further 213,835 m2 to the total area.
Tenerife is known internationally as the "Island of Eternal Spring" (Isla de la Eterna Primavera).[36] The island, being on a latitude of the Sahara Desert, enjoys a warm climate year-round with an average of 20° - 22°C in the winter and 26° - 28°C in the summer and high sunshine totals. The moderate climate of Tenerife is controlled to a great extent by the tradewinds, whose humidity, principally, is condensed over the north and northeast of the island, creating cloud banks that range between 600 and 1,800 meters in height. The cold sea currents of the Canary Islands, also have a cooling effect on the coasts and its beaches and the topography of the landscape plays a role in climatic differences on the island with its many valleys.
The average temperatures, however, can fluctuate between 17-18°C and 24-25°C in the winter season. Evidently there are climatic contrasts which do occur on the island, particularly during the winter months when it is possible to enjoy the warm sunshine on the coast and experience snow within just miles, 3000 metres above sea level on Teide. There is also a contrast in climate between different parts of the island at a lower altitude, even in proximity, notably between the cities of Santa Cruz de Tenerife and San Cristóbal de La Laguna. Santa Cruz generally experiences a warm climate throughout the year with temperatures noticeably greater than at the bordering La Laguna, where frequently it is colder with a greater chance of rainfall.
The north and the south of Tenerife similarly have different climatic characteristics. The windward side of the island receives 73% of all precipitation on the island, and the relative humidity of the air is superior and the insolation inferior. The pluviometric maximums are registered on the windward side at an average altitude of between 1.000-1.200 ms, almost exclusively in the La Orotava mountain range. However, although climatic differences in rainfall and sunshine on the island exist, overall annual precipitation is very low with some of the summer months often not receiving any days of rainfall. In June and July in particular it is rare to receive any. The wettest season is during the winter, but in December, for instance, an average of five days of rainfall can be expected, and even this is partly attributed to snowfall on Teide.
Santa Cruz de Tenerife is the capital of the island and the seat of the island council . The city is capital of the autonomous community of Canary Islands , sharing governmental institutions such as Presidency and ministries. Between the 1833 territorial division of Spain and 1927 Santa Cruz de Tenerife was the sole capital of the Canary Islands, until in 1927 a decree ordered that the capital of the Canary Islands be shared, as it remains as at present.
The island is home to the University of San Fernando de La Laguna, which was founded in 1792. The University of La Laguna is the oldest university in the Canaries. San Cristóbal de La Laguna is the second city of the island and the third one of the archipelago. The city of La Laguna was also capital of the Canary Islands until Santa Cruz replaced it in 1833.
Tenerife also has the highest elevation of Spain, a World Heritage Site that is the third largest volcano in the world from its base, El Teide.
Tenerife is a rugged and volcanic island sculpted by successive eruptions throughout its history. There are four historically recorded volcanic eruptions, none of which has led to casualties. The first occurred in 1704, when the Arafo, Fasnia and Siete Fuentes volcanoes erupted simultaneously. Two years later, in 1706, the greatest eruption occurred at Trevejo. This volcano produced great quantities of lava which buried the city and port of Garachico. The last eruption of the 18th century happened in 1798 at Cañadas de Teide, in Chahorra. Finally, and most recently, in 1909 the Chinyero volcano, in the municipality of Santiago del Teide, erupted.
The island is located between 28º and 29º N and the 16º and 17º meridian. It is situated north of the Tropic of Cancer, occupying a central position between the other Canary Islands of Gran Canaria, La Gomera and La Palma. The island is about 300 km (186 mi) from the African coast, and approximately 1,000 km from the Iberian Peninsula. Tenerife is the largest island of the Canary Islands archipelago, with a surface area of 2,034.38 km2 and the longest coastline amounting to 342 km.
In addition, the highest point, Mount Teide, with an elevation of 3,718 m above sea level is the highest point in all of Spain. It comprises about 200 small barren islets or large rocks including Roques de Anaga, Roque de Garachico, and Fasnia adding a further 213,835 m2 to the total area.
Tenerife is known internationally as the "Island of Eternal Spring" (Isla de la Eterna Primavera).[36] The island, being on a latitude of the Sahara Desert, enjoys a warm climate year-round with an average of 20° - 22°C in the winter and 26° - 28°C in the summer and high sunshine totals. The moderate climate of Tenerife is controlled to a great extent by the tradewinds, whose humidity, principally, is condensed over the north and northeast of the island, creating cloud banks that range between 600 and 1,800 meters in height. The cold sea currents of the Canary Islands, also have a cooling effect on the coasts and its beaches and the topography of the landscape plays a role in climatic differences on the island with its many valleys.
The average temperatures, however, can fluctuate between 17-18°C and 24-25°C in the winter season. Evidently there are climatic contrasts which do occur on the island, particularly during the winter months when it is possible to enjoy the warm sunshine on the coast and experience snow within just miles, 3000 metres above sea level on Teide. There is also a contrast in climate between different parts of the island at a lower altitude, even in proximity, notably between the cities of Santa Cruz de Tenerife and San Cristóbal de La Laguna. Santa Cruz generally experiences a warm climate throughout the year with temperatures noticeably greater than at the bordering La Laguna, where frequently it is colder with a greater chance of rainfall.
The north and the south of Tenerife similarly have different climatic characteristics. The windward side of the island receives 73% of all precipitation on the island, and the relative humidity of the air is superior and the insolation inferior. The pluviometric maximums are registered on the windward side at an average altitude of between 1.000-1.200 ms, almost exclusively in the La Orotava mountain range. However, although climatic differences in rainfall and sunshine on the island exist, overall annual precipitation is very low with some of the summer months often not receiving any days of rainfall. In June and July in particular it is rare to receive any. The wettest season is during the winter, but in December, for instance, an average of five days of rainfall can be expected, and even this is partly attributed to snowfall on Teide.
Guinea-Bissau
The Republic of Guinea-Bissau is located in West Africa. It is bordered by Senegal to the north, and Guinea to the south and east, with the Atlantic Ocean to its west.
It covers nearly 37,000 square kilometres with an estimated population of 1,600,000. Formerly the Portuguese colony of Portuguese Guinea, upon independence, the name of its capital, Bissau, was added to the country's name to prevent confusion with the Republic of Guinea. The country's per-capita gross domestic product is one of the lowest in the world.
Guinea-Bissau was once part of the kingdom of Gabu, part of the Mali Empire; parts of this kingdom persisted until the eighteenth century, while others were part of the Portuguese Empire. Portuguese Guinea was known also, from its main economic activity, as the Slave Coast.
Early reports of Europeans reaching this area include those of the Venetian Alvise Cadamosto's voyage of 1455, the 1479-1480 voyage by Flemish-French trader Eustache de la Fosse, and Diogo Cão who in the 1480s reached the Congo River and the lands of Bakongo, setting up thus the foundations of modern Angola, some 1200 km down the African coast from Guinea-Bissau.
Although the rivers and coast of this area were among the first places colonized by the Portuguese, since the 16th century, the interior was not explored until the nineteenth century. The local African rulers in Guinea, some of whom prospered greatly from the slave trade, had no interest in allowing the Europeans any further inland than the fortified coastal settlements where the trading took place. African communities that fought back against slave traders had even greater incentives to distrust European adventurers and would-be settlers. The Portuguese presence in Guinea was therefore largely limited to the port of Bissau and Cacheu, although isolated European farmer-settlers established farms along Bissau's inland rivers.
For a brief period in the 1790s the British attempted to establish a rival foothold on an offshore island, at Bolama. But by the 19th century the Portuguese were sufficiently secure in Bissau to regard the neighbouring coastline as their own special territory, also up north in part of present South Senegal.
An armed rebellion beginning in 1956 by the African Party for the Independence of Guinea and Cape Verde under the leadership of Amílcar Cabral gradually consolidated its hold on then Portuguese Guinea. Unlike guerrilla movements in other Portuguese colonies, the PAIGC rapidly extended its military control over large portions of the territory, aided by the jungle-like terrain, its easily reached borderlines with neighbouring allies and large quantities of arms from Cuba, China, the Soviet Union, and left-leaning African countries.
Cuba also agreed to supply artillery experts, doctors and technicians. The PAIGC even managed to acquire a significant anti-aircraft capability in order to defend itself against aerial attack. By 1973, the PAIGC was in control of many parts of Guinea. Independence was unilaterally declared on September 24, 1973. Recognition became universal following the April 25, 1974 socialist-inspired military coup in Portugal which overthrew Lisbon's Estado Novo regime.
Luís Cabral was appointed the first President of Guinea-Bissau. Following independence local black soldiers that fought along with the Portuguese Army against the PAIGC guerrillas were slaughtered by the thousands. Some managed to escape and settled in Portugal or other African nations, one of the massacres occurred in the town of Bissorã. In 1980 the PAIGC admitted in its newspaper "Nó Pintcha" that many were executed and buried in unmarked collective graves in the woods of Cumerá, Portogole and Mansabá.
The country was controlled by a revolutionary council until 1984. The first multi-party elections were held in 1994, but an army uprising in 1998 led to the president's ousting and the Guinea-Bissau Civil War. Elections were held again in 2000 and Kumba Ialá was elected president.
In September 2003, a coup took place in which the military arrested Ialá on the charge of being "unable to solve the problems." After being delayed several times, legislative elections were held in March 2004 . A mutiny of military factions in October 2004 resulted in the death of the head of the armed forces, and caused widespread unrest.
It covers nearly 37,000 square kilometres with an estimated population of 1,600,000. Formerly the Portuguese colony of Portuguese Guinea, upon independence, the name of its capital, Bissau, was added to the country's name to prevent confusion with the Republic of Guinea. The country's per-capita gross domestic product is one of the lowest in the world.
Guinea-Bissau was once part of the kingdom of Gabu, part of the Mali Empire; parts of this kingdom persisted until the eighteenth century, while others were part of the Portuguese Empire. Portuguese Guinea was known also, from its main economic activity, as the Slave Coast.
Early reports of Europeans reaching this area include those of the Venetian Alvise Cadamosto's voyage of 1455, the 1479-1480 voyage by Flemish-French trader Eustache de la Fosse, and Diogo Cão who in the 1480s reached the Congo River and the lands of Bakongo, setting up thus the foundations of modern Angola, some 1200 km down the African coast from Guinea-Bissau.
Although the rivers and coast of this area were among the first places colonized by the Portuguese, since the 16th century, the interior was not explored until the nineteenth century. The local African rulers in Guinea, some of whom prospered greatly from the slave trade, had no interest in allowing the Europeans any further inland than the fortified coastal settlements where the trading took place. African communities that fought back against slave traders had even greater incentives to distrust European adventurers and would-be settlers. The Portuguese presence in Guinea was therefore largely limited to the port of Bissau and Cacheu, although isolated European farmer-settlers established farms along Bissau's inland rivers.
For a brief period in the 1790s the British attempted to establish a rival foothold on an offshore island, at Bolama. But by the 19th century the Portuguese were sufficiently secure in Bissau to regard the neighbouring coastline as their own special territory, also up north in part of present South Senegal.
An armed rebellion beginning in 1956 by the African Party for the Independence of Guinea and Cape Verde under the leadership of Amílcar Cabral gradually consolidated its hold on then Portuguese Guinea. Unlike guerrilla movements in other Portuguese colonies, the PAIGC rapidly extended its military control over large portions of the territory, aided by the jungle-like terrain, its easily reached borderlines with neighbouring allies and large quantities of arms from Cuba, China, the Soviet Union, and left-leaning African countries.
Cuba also agreed to supply artillery experts, doctors and technicians. The PAIGC even managed to acquire a significant anti-aircraft capability in order to defend itself against aerial attack. By 1973, the PAIGC was in control of many parts of Guinea. Independence was unilaterally declared on September 24, 1973. Recognition became universal following the April 25, 1974 socialist-inspired military coup in Portugal which overthrew Lisbon's Estado Novo regime.
Luís Cabral was appointed the first President of Guinea-Bissau. Following independence local black soldiers that fought along with the Portuguese Army against the PAIGC guerrillas were slaughtered by the thousands. Some managed to escape and settled in Portugal or other African nations, one of the massacres occurred in the town of Bissorã. In 1980 the PAIGC admitted in its newspaper "Nó Pintcha" that many were executed and buried in unmarked collective graves in the woods of Cumerá, Portogole and Mansabá.
The country was controlled by a revolutionary council until 1984. The first multi-party elections were held in 1994, but an army uprising in 1998 led to the president's ousting and the Guinea-Bissau Civil War. Elections were held again in 2000 and Kumba Ialá was elected president.
In September 2003, a coup took place in which the military arrested Ialá on the charge of being "unable to solve the problems." After being delayed several times, legislative elections were held in March 2004 . A mutiny of military factions in October 2004 resulted in the death of the head of the armed forces, and caused widespread unrest.
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