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Horse Latitudes
The horse latitudes are the latitudes about 30 degrees north and south of the Equator. They are characterized by sunny skies, calm winds, and very little precipitation. They are also known as subtropical ridges, or highs. It is a high-pressure area at the divergence of trade winds and the westerlies. Origin of the term A likely and documented explanation is that the term is derived from the "dead horse" ritual of seamen (see Beating a dead horse). In this practice, the seaman paraded a straw-stuffed effigy of a horse around the deck before throwing it overboard. Seamen were paid partly in advance before a long voyage, and they frequently spent their pay all at once, resulting in a period of time without income. If they got advances from the ship's paymaster, they would incur debt. This period was called the "dead horse" time, and it usually lasted a month or two. The seaman's ceremony was to celebrate having worked off the "dead horse" debt. As west-bound shipping from Europe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Circulation
Atmospheric circulation is the large-scale movement of air and together with ocean circulation is the means by which thermal energy is redistributed on the surface of the Earth. The Earth's atmospheric circulation varies from year to year, but the large-scale structure of its circulation remains fairly constant. The smaller scale weather systems – mid-latitude depressions, or tropical convective cells – occur chaotically, and long-range weather predictions of those cannot be made beyond ten days in practice, or a month in theory (see chaos theory and the butterfly effect). The Earth's weather is a consequence of its illumination by the Sun and the laws of thermodynamics. The atmospheric circulation can be viewed as a heat engine driven by the Sun's energy and whose energy sink, ultimately, is the blackness of space. The work produced by that engine causes the motion of the masses of air, and in that process it redistributes the energy absorbed by the Earth's surface ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rodwell–Hoskins Mechanism
Rodwell–Hoskins mechanism is a hypothesis about a climatic teleconnection between the Indian/Asian summer monsoon and the climate of the Mediterranean. It stipulates that ascending air in the monsoon region induces atmospheric circulation features named Rossby waves that expand westward and interact with the mean westerly winds of the midlatitudes, eventually inducing descent of the air. Descending air warms and its humidity decreases, thus resulting in a drier climate during the summer months. The interaction of this atmospheric flow with the topography such as the Atlas and Zagros mountains further modifies the effect. This hypothesis has been advanced to explain the dry climate of the eastern Mediterranean during the summer months, as other explanations involving the Hadley circulation are not plausible during that season. Together with sea and land surface feedbacks it may also explain the existence of deserts and subtropical anticyclones elsewhere in the world, as well ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kalahari Desert
The Kalahari Desert is a large semi-arid sandy savanna in Southern Africa extending for , covering much of Botswana, and parts of Namibia and South Africa. It is not to be confused with the Angolan, Namibian, and South African Namib coastal desert, whose name is of Khoekhoegowab origin and means "vast place". Etymology ''Kalahari'' is derived from the Tswana word ''Kgala'', meaning "the great thirst", or ''Kgalagadi'', meaning "a waterless place"; the Kalahari has vast areas covered by red sand without any permanent surface water. History The Kalahari Desert was not always a dry desert. The fossil flora and fauna from Gcwihaba Cave in Botswana indicates that the region was much wetter and cooler at least from 30 to 11 thousand BP (before present) especially after 17,500 BP. Geography Drainage of the desert is by dry black valleys, seasonally inundated pans and the large salt pans of the Makgadikgadi Pan in Botswana and Etosha Pan in Namibia. The only permanent riv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atacama Desert
The Atacama Desert ( es, Desierto de Atacama) is a desert plateau in South America covering a 1,600 km (990 mi) strip of land on the Pacific coast, west of the Andes Mountains. The Atacama Desert is the driest nonpolar desert in the world, and the second driest overall, just behind some very specific spots within the McMurdo Dry Valleys as well as the only hot true desert to receive less precipitation than the polar deserts, and the largest fog desert in the world. Both regions have been used as experimentation sites on Earth for Mars expedition simulations. The Atacama Desert occupies , or if the barren lower slopes of the Andes are included. Most of the desert is composed of stony terrain, salt lakes (''salares''), sand, and felsic lava that flows towards the Andes. The desert owes its extreme aridity to a constant temperature inversion due to the cool north-flowing Humboldt ocean current and to the presence of the strong Pacific anticyclone. The most arid r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sonoran Desert
The Sonoran Desert ( es, Desierto de Sonora) is a desert in North America and ecoregion that covers the northwestern Mexican states of Sonora, Baja California, and Baja California Sur, as well as part of the southwestern United States (in Arizona and California). It is the hottest desert in both Mexico and the United States. It has an area of . In phytogeography, the Sonoran Desert is within the Sonoran Floristic province of the Madrean Region of southwestern North America, part of the Holarctic realm of the northern Western Hemisphere. The desert contains a variety of unique endemic plants and animals, notably, the saguaro (''Carnegiea gigantea'') and organ pipe cactus (''Stenocereus thurberi''). The Sonoran Desert is clearly distinct from nearby deserts (e.g., the Great Basin, Mojave, and Chihuahuan deserts) because it provides subtropical warmth in winter and two seasons of rainfall (in contrast, for example, to the Mojave's dry summers and cold winters). This creat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mojave Desert
The Mojave Desert ( ; mov, Hayikwiir Mat'aar; es, Desierto de Mojave) is a desert in the rain shadow of the Sierra Nevada mountains in the Southwestern United States. It is named for the indigenous Mojave people. It is located primarily in southeastern California and southwestern Nevada, with small portions extending into Arizona and Utah. The Mojave Desert, together with the Sonoran, Chihuahuan, and Great Basin deserts, forms a larger North American Desert. Of these, the Mojave is the smallest and driest. The Mojave Desert displays typical basin and range topography, generally having a pattern of a series of parallel mountain ranges and valleys. It is also the site of Death Valley, which is the lowest elevation in North America. The Mojave Desert is often colloquially called the "high desert", as most of it lies between . It supports a diversity of flora and fauna. The desert supports a number of human activities, including recreation, ranching, and military train ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syrian Desert
The Syrian Desert ( ar, بادية الشام ''Bādiyat Ash-Shām''), also known as the North Arabian Desert, the Jordanian steppe, or the Badiya, is a region of desert, semi-desert and steppe covering of the Middle East, including parts of southern Syria, eastern Jordan, northern Saudi Arabia, and western Iraq. It accounts for 85% of the land area of Jordan and 55% of Syria. To the south it borders and merges into the Arabian Desert. The land is open, rocky or gravelly desert pavement, cut with occasional wadis. Location and name The desert is bounded by the Orontes Valley and the volcanic field of Harrat al-Shamah to the west, and by the Euphrates to the east. In the north, the desert gives way to the more fertile areas and to the south it runs into the deserts of the Arabian Peninsula. Some sources equate the Syrian Desert with the ''"Hamad Desert"'' while others limit the name ''Hamad'' to the southern central plateau. A few consider the Hamad to be the whole region ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sahara Desert
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Tropic Of Capricorn
The Tropic of Capricorn (or the Southern Tropic) is the circle of latitude that contains the subsolar point at the December (or southern) solstice. It is thus the southernmost latitude where the Sun can be seen directly overhead. It also reaches 90 degrees below the horizon at solar midnight on the June Solstice. Its northern equivalent is the Tropic of Cancer. The Tropic of Capricorn is one of the five major circles of latitude marked on maps of Earth. Its latitude is currently south of the Equator, but it is very gradually moving northward, currently at the rate of 0.47 arcseconds, or 15 metres, per year. Less than 3% of the world's population lives south of it; this is equivalent to about 30% of the population of the Southern Hemisphere. Name When this line of latitude was named in the last centuries BC, the Sun was in the constellation Capricornus at the December solstice. This is the date each year when the Sun reaches zenith at this latitude, the southernmost ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tropic Of Cancer
The Tropic of Cancer, which is also referred to as the Northern Tropic, is the most northerly circle of latitude on Earth at which the Sun can be directly overhead. This occurs on the June solstice, when the Northern Hemisphere is tilted toward the Sun to its maximum extent. It also reaches 90 degrees below the horizon at solar midnight on the December Solstice. Using a continuously updated formula, the circle is currently north of the Equator. Its Southern Hemisphere counterpart, marking the most southerly position at which the Sun can be directly overhead, is the Tropic of Capricorn. These tropics are two of the five major circles of latitude that mark maps of Earth, the others being the Arctic and Antarctic circles and the Equator. The positions of these two circles of latitude (relative to the Equator) are dictated by the tilt of Earth's axis of rotation relative to the plane of its orbit, and since the tilt changes, the location of these two circles also chang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monsoon
A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with annual latitudinal oscillation of the Intertropical Convergence Zone (ITCZ) between its limits to the north and south of the equator. Usually, the term monsoon is used to refer to the rainy phase of a seasonally changing pattern, although technically there is also a dry phase. The term is also sometimes used to describe locally heavy but short-term rains. The major monsoon systems of the world consist of the West African, Asia–Australian, the North American, and South American monsoons. The term was first used in English in British India and neighboring countries to refer to the big seasonal winds blowing from the Bay of Bengal and Arabian Sea in the southwest bringing heavy rainfall to the area. Etymology The etymology of the word monsoon is not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
