|
Geography Of Antarctica
The geography of Antarctica is dominated by its south polar location and, thus, by ice. The Antarctic continent, located in the Earth's southern hemisphere, is centered asymmetrically around the South Pole and largely south of the Antarctic Circle. It is washed by the Southern (or Antarctic) Ocean or, depending on definition, the southern Pacific, Atlantic, and Indian Oceans. It has an area of more than . Antarctica is the largest ice desert in the world. Some 98% of Antarctica is covered by the Antarctic ice sheet, the world's largest ice sheet and also its largest reservoir of fresh water. Averaging at least thick, the ice is so massive that it has depressed the continental bedrock in some areas more than below sea level; subglacial lakes of liquid water also occur (e.g. Lake Vostok). Ice shelves and rises populate the ice sheet on the periphery. The present Antarctic ice sheet accounts for 90 percent of Earth's total ice volume and 70 percent of its fresh water. It ho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. Antarctica is the fifth-largest continent, being about 40% larger than Europe, and has an area of . Most of Antarctica is covered by the Antarctic ice sheet, with an average thickness of . Antarctica is, on average, the coldest, driest, and windiest of the continents, and it has the highest average elevation. It is mainly a polar desert, with annual Climate of Antarctica#Precipitation, precipitation of over along the coast and far less inland. About 70% of the world's freshwater reserves are frozen in Antarctica, which, if melted, would raise global sea levels by almost . Antarctica holds the record for the Lowest temperature recorded on Earth, lowest measured temperature on Earth, . The coastal regions can reach temperatures over in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polar Region
The polar regions, also called the frigid zones or polar zones, of Earth are Earth's polar ice caps, the regions of the planet that surround its geographical poles (the North and South Poles), lying within the polar circles. These high latitudes are dominated by floating sea ice covering much of the Arctic Ocean in the north, and by the Antarctic ice sheet on the continent of Antarctica and the Southern Ocean in the south. Definitions The Arctic has various definitions, including the region north of the Arctic Circle (currently Epoch 2010 at 66°33'44" N), or just the region north of 60° north latitude, or the region from the North Pole south to the timberline. The Antarctic is usually defined simply as south of 60° south latitude, or the continent of Antarctica. The 1959 Antarctic Treaty uses the former definition. The two polar regions are distinguished from the other two climatic and biometric belts of Earth, a tropics belt near the equator, and two middle latitud ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Post-glacial Rebound
Post-glacial rebound (also called isostatic rebound or crustal rebound) is the rise of land masses after the removal of the huge weight of ice sheets during the last glacial period, which had caused isostatic depression. Post-glacial rebound and isostatic depression are phases of glacial isostasy (glacial isostatic adjustment, glacioisostasy), the deformation of the Earth's crust in response to changes in ice mass distribution. The direct raising effects of post-glacial rebound are readily apparent in parts of Northern Eurasia, Northern America, Patagonia, and Antarctica. However, through the processes of ''ocean siphoning'' and ''continental levering'', the effects of post-glacial rebound on sea level are felt globally far from the locations of current and former ice sheets.Milne, G.A., and J.X. Mitrovica (2008) ''Searching for eustasy in deglacial sea-level histories.'' Quaternary Science Reviews. 27:2292–2302. Overview During the last glacial period, much of northern Euro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fresh Water
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salt (chemistry), salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mineral water, mineral-rich waters, such as chalybeate springs. Fresh water may encompass frozen water, frozen and meltwater in ice sheets, ice caps, glaciers, snowfields and icebergs, natural precipitations such as rainfall, snowfall, hail/ice pellets, sleet and graupel, and surface runoffs that form inland bodies of water such as wetlands, ponds, lakes, rivers, streams, as well as groundwater contained in aquifers, subterranea (geography), subterranean subterranean river, rivers and underground lake, lakes. Water is critical to the survival of all living organisms. Many organisms can thrive on salt water, but the great majority of vascular plants and most insects, amphibians, reptiles, mammals and birds need fresh water to sur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Sheet
In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacier, glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are the Antarctic ice sheet and the Greenland ice sheet. Ice sheets are bigger than ice shelf, ice shelves or alpine glaciers. Masses of ice covering less than 50,000 km2 are termed an ice cap. An ice cap will typically feed a series of glaciers around its periphery. Although the surface is cold, the base of an ice sheet is generally warmer due to Geothermal activity, geothermal heat. In places, melting occurs and the melt-water lubricates the ice sheet so that it flows more rapidly. This process produces fast-flowing channels in the ice sheet — these are ice streams. Even stable ice sheets are continually in motion as the ice gradually flows outward from the central plateau, which is the tallest point of the ice sheet, and towards the margins. The ice sheet slope is low around the plate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Ice Sheet
The Antarctic ice sheet is a continental glacier covering 98% of the Antarctic continent, with an area of and an average thickness of over . It is the largest of Earth's two current ice sheets, containing of ice, which is equivalent to 61% of all fresh water on Earth. Its surface is nearly continuous, and the only ice-free areas on the continent are the dry valleys, nunataks of the Antarctic mountain ranges, and sparse coastal bedrock. However, it is often subdivided into the East Antarctic ice sheet (EAIS), West Antarctic ice sheet (WAIS), and Antarctic Peninsula (AP), due to the large differences in topography, ice flow, and glacier mass balance between the three regions. Because the East Antarctic ice sheet is over 10 times larger than the West Antarctic ice sheet and located at a higher elevation, it is less vulnerable to climate change than the WAIS. In the 20th century, EAIS had been one of the only places on Earth which displayed limited cooling instead of warming, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indian Ocean
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), Australia to the east. To the south it is bounded by the Southern Ocean or Antarctica, depending on the definition in use. The Indian Ocean has large marginal or regional seas, including the Andaman Sea, the Arabian Sea, the Bay of Bengal, and the Laccadive Sea. Geologically, the Indian Ocean is the youngest of the oceans, and it has distinct features such as narrow continental shelf, continental shelves. Its average depth is 3,741 m. It is the warmest ocean, with a significant impact on global climate due to its interaction with the atmosphere. Its waters are affected by the Indian Ocean Walker circulation, resulting in unique oceanic currents and upwelling patterns. The Indian Ocean is ecologically diverse, with important ecosystems such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlantic Ocean
The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for separating the New World of the Americas (North America and South America) from the Old World of Afro-Eurasia (Africa, Asia, and Europe). Through its separation of Afro-Eurasia from the Americas, the Atlantic Ocean has played a central role in the development of human society, globalization, and the histories of many nations. While the Norse colonization of North America, Norse were the first known humans to cross the Atlantic, it was the expedition of Christopher Columbus in 1492 that proved to be the most consequential. Columbus's expedition ushered in an Age of Discovery, age of exploration and colonization of the Americas by European powers, most notably Portuguese Empire, Portugal, Spanish Empire, Sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the continents of Asia and Australia in the west and the Americas in the east. At in area (as defined with a southern Antarctic border), the Pacific Ocean is the largest division of the World Ocean and the hydrosphere and covers approximately 46% of Earth's water surface and about 32% of the planet's total surface area, larger than its entire land area ().Pacific Ocean . ''Encyclopædia Britannica, Britannica Concise.'' 2008: Encyclopædia Britannica, Inc. The centers of both the Land and water hemispheres, water hemisphere and the Western Hemisphere, as well as the Pole of inaccessi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southern Ocean
The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the world ocean, generally taken to be south of 60th parallel south, 60° S latitude and encircling Antarctica. With a size of , it is the second-smallest of the five principal oceanic divisions, smaller than the Pacific Ocean, Pacific, Atlantic Ocean, Atlantic and Indian Ocean, Indian oceans, and larger than the Arctic Ocean. The maximum depth of the Southern Ocean, using the definition that it lies south of 60th parallel, was surveyed by the Five Deeps Expedition in early February 2019. The expedition's multibeam sonar team identified the deepest point at 60° 28' 46"S, 025° 32' 32"W, with a depth of . The expedition leader and chief submersible pilot Victor Vescovo, has proposed naming this deepest point the "Factorian Deep", based on the name of the crewed submersible ''DSV Limiting Factor'', in which he successfully visited the bottom for the first time on February 3, 2019 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Circle
The Antarctic Circle is the most southerly of the five major circles of latitude that mark maps of Earth. The region south of this circle is known as the Antarctic, and the zone immediately to the north is called the Southern Temperate Zone. South of the Antarctic Circle, the Sun is above the horizon for 24 continuous hours at least once per year (and therefore visible at solar midnight) and the centre of the Sun (ignoring refraction) is below the horizon for 24 continuous hours at least once per year (and therefore not visible at solar noon); this is also true within the Arctic Circle, the Antarctic Circle’s counterpart in the Northern Hemisphere. The position of the Antarctic Circle is not fixed and, not taking account of the nutation, currently runs south of the Equator. This figure may be slightly inaccurate because it does not allow for the effects of astronomical nutation, which can be up to 10″. Its latitude depends on the Earth's axial tilt, which fluctuates within ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Pole
The South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is the point in the Southern Hemisphere where the Earth's rotation, Earth's axis of rotation meets its surface. It is called the True South Pole to distinguish from the south magnetic pole. The South Pole is by definition the southernmost point on the Earth, lying antipode (geography), antipodally to the North Pole. It defines geodetic latitude 90° South, as well as the direction of true south. At the South Pole all directions point North; all lines of longitude converge there, so its longitude can be defined as any degree value. No time zone has been assigned to the South Pole, so any time can be used as the local time. Along tight latitude circles, clockwise is east and counterclockwise is west. The South Pole is at the center of the Southern Hemisphere. Situated on the continent of Antarctica, it is the site of the United States Amundsen–Scott South Pole Station, which was established in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
