An equator of a rotating spheroid is its zeroth circle of latitude. It is the imaginary line on the spheroid, equidistant from its poles, dividing it into northern and southern hemispheres. In other words, it is the intersection of the spheroid with the plane perpendicular to its axis of rotation and midway between its geographical poles. On Earth, the Equator is 21.3 % over land. Indonesia is the country straddling the greatest length of the equatorial line across both land and sea; the name is derived from medieval Latin word aequator, in the phrase circulus aequator diei et noctis, meaning ‘circle equalizing day and night’, from the Latin word aequare meaning ‘make equal’. The latitude of the Earth's equator is, by definition, 0° of arc; the Equator is one of the five notable circles of latitude on Earth. The Equator is the only line of latitude, a great circle — that is, one whose plane passes through the center of the globe; the plane of Earth's equator, when projected outwards to the celestial sphere, defines the celestial equator.
In the cycle of Earth's seasons, the equatorial plane runs through the Sun twice per year: on the equinoxes in March and September. To a person on Earth, the Sun appears to travel above the Equator at these times. Light rays from the Sun's center are perpendicular to Earth's surface at the point of solar noon on the Equator. Locations on the Equator experience the shortest sunrises and sunsets because the Sun's daily path is nearly perpendicular to the horizon for most of the year; the length of daylight is constant throughout the year. Earth bulges at the Equator. Sites near the Equator, such as the Guiana Space Centre in Kourou, French Guiana, are good locations for spaceports as they have a faster rotational speed than other latitudes. Since Earth rotates eastward, spacecraft must be launched eastward to take advantage of this Earth-boost of speed; the precise location of the Equator is not fixed. This effect must be accounted for in detailed geophysical measurements; the International Association of Geodesy and the International Astronomical Union have chosen to use an equatorial radius of 6,378.1366 kilometres.
This equatorial radius is in the 2003 and 2010 IERS Conventions. It is the equatorial radius used for the IERS 2003 ellipsoid. If it were circular, the length of the Equator would be 2π times the radius, namely 40,075.0142 kilometres. The GRS 80 as approved and adopted by the IUGG at its Canberra, Australia meeting of 1979 has an equatorial radius of 6,378.137 kilometres. The WGS 84, a standard for use in cartography and satellite navigation including GPS has an equatorial radius of 6,378.137 kilometres. For both GRS 80 and WGS 84, this results in a length for the Equator of 40,075.0167 km. The geographical mile is defined as one arc-minute of the Equator, so it has different values depending on which radius is assumed. For example, by WSG-84, the distance is 1,855.3248 metres, while by IAU-2000, it is 1,855.3257 metres. This is a difference of less than one millimetre over the total distance; the earth is modeled as a sphere flattened 0.336% along its axis. This makes the Equator 0.16% longer than a meridian.
The IUGG standard meridian is, to the nearest millimetre, 40,007.862917 kilometres, one arc-minute of, 1,852.216 metres, explaining the SI standardization of the nautical mile as 1,852 metres, more than 3 metres less than the geographical mile. The sea-level surface of the Earth is irregular, so the actual length of the Equator is not so easy to determine. Aviation Week and Space Technology on 9 October 1961 reported that measurements using the Transit IV-A satellite had shown the equatorial "diameter" from longitude 11° West to 169° East to be 1,000 feet greater than its "diameter" ninety degrees away; the Equator passes through the land of 11 countries. Starting at the Prime Meridian and heading eastwards, the Equator passes through: Despite its name, no part of Equatorial Guinea lies on the Equator. However, its island of Annobón is 155 km south of the Equator, the rest of the country lies to the north. Seasons result from the tilt of the Earth's axis compared to the plane of its revolution around the Sun.
Throughout the year the northern and southern hemispheres are alternately turned either toward or away from the sun depending on Earth's position in its orbit. The hemisphere turned toward the sun receives more sunlight and is in summer, while the other hemisphere receives less sun and is in winter. At the equinoxes, the Earth's axis
The Turkwel River is a river flowing from Mount Elgon in the border of Kenya and Uganda to Lake Turkana. The river is called the Suam River from its source to the border with the West Pokot County of Kenya; the name Turkwel is derived from the Turkana name for the river, Tir-kol, which means translates to a river that "withstands the wilderness". The Turkwel begins from the lush green slopes of Mount Elgon and the Cherangani Hills, traverses the Southern Turkana Plains, crosses Loturerei Desert near Lodwar and empties to the world's largest desert lake, Lake Turkana; the river's flow is seasonally varied, it is subject to flash floods in the rainy season. The controversial Turkwel Dam was built by the Kenyan government from 1986 to 1991 with the help of France; the plan was to harness the waters of the Turkwel. The project was supposed to cost 4 billion Kenyan shillings, but ended up costing more than 20 billion; the dam filled the Turkwel Gorge and created the Turkwel Gorge Reservoir
The Athi-Galana-Sabaki River is the second longest river in Kenya. It has a total length of 390 km, drains an area of 70 000 km²; the river enters the Indian Ocean as the Galana River. The Athi River flows across the Kapote and Athi plains, through Athi River town takes a northeast direction where it is met by the Nairobi River. Near Thika the river forms the Fourteen Falls and turns south-south-east under the wooded slopes of the Yatta ridge, which shuts in its basin on the east. Apart from the numerous small feeders of the upper river the only tributary is the Tsavo River, from the east side of Kilimanjaro, which enters at about 3° S, it turns east, in its lower course is known as the Sabaki River, which traverses the sterile quartz-land of the outer plateau. The valley is low and flat, covered with forest and scrub, containing small lakes and backwaters connected to the river during the rainy season. During the rainy season, the stream rises as much as 10 m in places, now flowing with a turbid yellow colour.
Flowing east, it enters the Indian Ocean in 3° 10′ S. 10 km north of Malindi town. The river flows through the Tsavo East National Park and attracts diverse wildlife, including hippopotamus and crocodiles. Famously, in the 2009 case of Ben Nyaumbe, the region is home to pythons. Google Maps, Galana River
Southern Ewaso Ng'iro
The Southern Ewaso Ng'iro is a river in the Great Rift Valley in Kenya. It plays an important role in the ecology of Lake Natron, the main regular breeding site for near-threatened lesser flamingos. Changes to land use in the river's headwaters or in the marshes before the river enters the lake could have a serious impact on this species; the Ewaso Ng ` iro rises on the Mau Escarpment. The forest, which plays an important role in regulating and filtering the inflow to the river, is under threat from logging and land clearance for farming. Destruction would increase sediment loads in the river and cause greater seasonal variance in the volume of water; the river flows south through the rift valley to the east of the Nguruman Escarpment. It crosses the border into Tanzania; the river, which runs all year round, is the main inflow to the lake. The river once flowed directly into the lake, but in geologically recent times it has been dammed by a horst beside the Shompole volcano; this has caused the waters to spread out into the expanding Engare Ng'iro swamp, where the river deposits its sediment.
The sediment-free river water seeps into the brine lake. The permanent swamp covers about 4,000 hectares. South of this a seasonal floodplain of about 8,000 hectares stretches down to Lake Natron and along its eastern shore; the Lake Natron basin has been designated a Wetlands of International Importance under the Ramsar Convention. However, in the past there have been plans to dam the Ewaso Ng'iro for hydroelectric power generation and for irrigation of the marshlands north of the lake, diverting water from other rivers to increase the flow; the plans would include creating a variable freshwater lagoon with an area of about 50 square kilometres. If implemented, the impact on the lake's ecology could be drastic. Reduced salinity and pollution with agri-chemicals could wipe out the blue-green algae that provide food for the lesser flamingo; the lake is the main breeding ground for this near-threatened species. As of 2007 the dam project appeared to be on hold
Tana River (Kenya)
The 1,000 kilometres long Tana River is the longest river in Kenya, gives its name to the Tana River County. Its tributaries include the Thika, as well as several smaller rivers that flow only during the rainy season; the river rises in the Aberdare Mountains to the west of Nyeri. It runs east before turning south around the massif of Mount Kenya; the river runs into the Masinga Reservoir and Kiambere Reservoir, created by Masinga and Kiambere dams respectively]. Masinga and Kiambere reservoirs serve a dual purpose, hydro-electric power generation and agricultural irrigation. Three further dams are located between Masinga and Kiambere, namely Kamburu and Kindaruma, that are used for HEP generation. Below the dams, the river turns north and flows along the north-south boundary between the Meru and North Kitui and Bisanadi and Rabole National Reserves. In the reserves the river turns east, south east, it passes through the towns of Garissa and Garsen before entering the Indian Ocean at the Ungwana Bay-Kipini area, at the end of a river delta that reaches 30 km upstream from the river mouth itself.
It runs through a desert, irrigates the surrounding land. Annual flow is above 5,000 million cubic meters on average, but varies both within and across years, includes two flood seasons each year. Between 1944 and 1978, average total flow was 6,105 MCM, varying from only 1,789 MCM in 1949 to 13,342 MCM in 1968. During the 1982-1996 period, annual flow remained above 5,000 MCM as well. A series of hydroelectric dams have been constructed along the river, including the Kindaruma Dam in 1968, the Kamburu Dam in 1975, the Gitaru Dam in 1978, the Masinga Dam in 1981, the Kiambere Dam in 1988. A 2003 study reported that two-thirds of Kenya's electrical needs were supplied by the series of dams along the Tana River. Water is drawn from the river by the following major irrigation projects: Bura Irrigation and Settlement Project, Tana Irrigation Scheme and the Tana Delta Irrigation Project. Two species of African reptiles are named after the Tana River: Leptotyphlops tanae and Lygosoma tanae. Tana River Primate Reserve Bura Irrigation and Settlement Project Securing water and land in the Tana Basin, Kenya: a resource book for water managers and practitioners "And the River Flowed On.
Namarunu is a shield volcano located in the Great Rift Valley, Kenya. Namarunu is located in the Suguta Valley, a section of the Kenyan Rift Valley just south of Lake Turkana, it extends from the western side of the rift past the center. The mountain forms a broad shield; the large basal part is about 200 metres deep, made up of outward-dipping trachytic lavas and tuffs. A few thousand years ago the Suguta was filled by a major lake, but now it is dry and hot, with only the small Lake Logipi at the northern end; some of the recent cones on the floor of the rift valley and on the eastern side of the rift below the Tirr Tirr Plateau contain hot springs. Namarunu was formed during the upper Pliocene, but has some material from the Holocene, it is a trachytic shield volcano topped by more recent parasitic cones and lava flows. The basal trachyte dates to 6.8 million years ago, while the uppermost basalts date to around 500,000 years ago. Large amounts of basalt were deposited in the Rift valley on the north and south of the volcano through effusion and explosions during the early Holocene.
A breached scoria cone that forms the summit of the mountain erupted fluid olivine basalts, with some eruptions than the period around 3,000 years ago when Lake Suguta dried out. Eruptions may have occurred around the same time as historical eruptions of the Barrier Volcano to the north. List of volcanoes in Kenya
Great Rift Valley, Kenya
The Great Rift Valley is part of an intra-continental ridge system that runs through Kenya from north to south. It is part of the Gregory Rift, the eastern branch of the East African Rift, which starts in Tanzania to the south and continues northward into Ethiopia, it was formed on the "Kenyan Dome" a geographical upwelling created by the interactions of three major tectonics: the Arabian and Somalian plates. In the past, it was seen as part of a "Great Rift Valley". Most of the valley falls within the former Rift Valley Province; the valley contains the Cherangani Hills and a chain of volcanoes. The climate is mild, with temperatures below 28 °C. Most rain falls during the March -- October -- November periods; the Tugen Hills to the west of Lake Baringo contain fossils preserved in lava flows from the period 14 to 4 million years ago. The relics of many hominids, ancestors of humans, were found here; the valley is bordered by escarpments to the west. The floor is broken by volcanoes, some still active, contains a series of lakes.
Some of the soils are Andisols, fertile soils from recent volcanic activity. Lake Turkana occupies the northern end of the Great Rift Valley in Kenya. There are volcanoes in Lake Turkana; the Suguta Valley, or Suguta Mud Flats, is an arid part of the Great Rift Valley directly south of Lake Turkana. The shield volcano Emuruangogolak straddles the valley to the south of Suguta, further south Mount Silali and Paka rise from the valley floor. Paka is a shield volcano, with widespread geothermal activity. South of Paka are Lake Baringo and Lake Bogoria. Menengai is a massive shield volcano in the floor of the rift with a caldera that formed about 8,000 years ago, it overlooks Lake Nakuru to the south. This region includes Lake Elementaita, Mount Kipipiri and Lake Naivasha; the Hell's Gate National Park lies south of Lake Naivasha. In the early 1900s, Mount Longonot erupted, ash can still be felt around Hell's Gate. Mount Longonot is a dormant stratovolcano located southeast of Lake Naivasha. Suswa is a shield volcano located between Nairobi.
Lava flows from the most recent eruptions are still not covered by vegetation, may be no more than one hundred years old. Lake Magadi is the most southern rift valley lake in Kenya, although the northern end of Lake Natron in Tanzania reaches into Kenya; the Elgeyo escarpment forms part of the western wall. The Kerio Valley lies between the Tugen Hills and the Elgeyo escarpment at an elevation of 1,000 metres There are large deposits of Fluorite in the Kerio Valley area. Further south the Mau Escarpment is a steep natural cliff 3,000 m high, running along the western edge of the Great Rift Valley about Lake Naivasha, yet further south the Nguruman Escarpment is around 50 kilometers long and elongated in N-W direction. Its northern edge is about 120 kilometres southwest of Nairobi, while the southern edge is near the Tanzanian border, at the northwestern corner of Lake Natron; the Aberdare Range forms a section of the eastern rim of the Great Rift Valley to the north of Nairobi. Mount Satima lies at the northern end of the Aberdares and is their highest point, Mount Kinangop at the southern end is the second highest.
The mountains form a ridge between these two peaks. Ngong Hills are peaks in a ridge along the east of the Great Rift Valley, located southwest near Nairobi. Kenya is home to 64 of the total lakes found within the continent of Africa. Eight of these make up the main lakes in the Kenyan Rift Valley. From north to south, the names of these lakes are Lake Turkana, Lake Logipi, Lake Baringo, Lake Bogoria, Lake Nakuru, Lake Elmenteita, Lake Naivasha, Lake Magadi Of those eight, only Lakes Baringo and Naivasha are fresh water. Lake Turkana, at the northern end of the rift, is 250 kilometres long, between 15 kilometres and 30 kilometres wide and is 125 metres at its greatest depth. Most of the other lakes are shallow and poorly drained, therefore have become alkaline, they have waters that are rich in blue-green algae, which feed insect larvae, small crustaceans and lesser flamingos. The larvae and crustaceans are food for greater flamingos. Massive flocks of these birds have been found to have an effect on the lakeside sediments also.
Their numbers cause trampling of the silts in certain areas, while the feeding grounds are oxygenated due to probing beaks in the mud. Their nest mounds can be preserved and cemented as the lake's water levels change; these form irregularities in the lakeside topography. Trona, an evaporative mineral, used for sodium carbonate production, has been mined at Lake Magadi for nearly 100 years, it produces about 250,000 metric tonnes per year. Other precious minerals like rubies and pink sapphires have been found and mined from areas around Lake Baringo. In 2004, over 2 kilograms of Corundum were collected. Three shallow alkaline lakes and the surrounding lands make up the Kenya Lake system: Lake Bogoria at 10,700 hectares, Lake Nakuru at 18,800 hectares and Lake Elementaita at 2,534 hectares; this system has one of the most diverse populations of birds in the world, is the home of thirteen globally threatened species of bird. It is an important nesting and breeding site for great white pelicans, is the most important feeding area for lesser flamingos in the world.
The system is home to globally important populations of black-necked grebe, African spoonbill, pied avocet, little grebe, yellow-billed stork, black-winged stilt, grey-headed gull and gull-billed tern. The Kenya Lake system is a key location on the West Asian-East African Flyway, a route followed by huge