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Whillans Ice Stream
Whillans Ice Stream () is a glaciological feature of the West Antarctic Ice Sheet, formerly known as Ice Stream B, renamed in 2001 in honor of Ohio State University glaciologist Ian Whillans. Research Whillans Ice Stream is one of about a half-dozen large, fast-moving rivers of ice pouring from the West Antarctic Ice Sheet into the Ross Ice Shelf. The ice stream is the subject of different glaciological studies, one of which is looking at subglacial lakes that researchers believe may be speeding the movement of the ice as they periodically fill and drain. Other researchers, also funded by the National Science Foundation, reported in the June 5, 2008 issue of the journal ''Nature'' that, from seismological and GPS data, they discovered the Whillans Ice Stream releases two bursts of seismic waves every day, each one equivalent to a magnitude 7 earthquake. The data show that the river of ice moves about a half-meter within approximately 30 minutes, remains still for 12 hours, then m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
West Antarctic Ice Sheet
The Western Antarctic Ice Sheet (WAIS) is the segment of the continental ice sheet that covers West Antarctica, the portion of Antarctica on the side of the Transantarctic Mountains that lies in the Western Hemisphere. The WAIS is classified as a marine-based ice sheet, meaning that its bed lies well below sea level and its edges flow into floating ice shelves. The WAIS is bounded by the Ross Ice Shelf, the Ronne Ice Shelf, and outlet glaciers that drain into the Amundsen Sea. Description It is estimated that the volume of the Antarctic ice sheet is about 25.4 million km3 (6.1 million cu mi), and the WAIS contains just under 10% of this, or 2.2 million km3 (530,000 cu mi). The weight of the ice has caused the underlying rock to sink by between in a process known as isostatic depression. Under the force of its own weight, the ice sheet deforms and flows. The interior ice flows slowly over rough bedrock. In some circumstances, ice can flow faster in ice streams, ... [...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, 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 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 measured temperature on Earth, . The coastal regions can reach temperatures over in summer. Native species of animals include mites, nematodes, penguins, seals and tardigrades. Where ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Christian Science Monitor
Christians () are people who follow or adhere to Christianity, a monotheistic Abrahamic religion based on the life and teachings of Jesus Christ. The words ''Christ'' and ''Christian'' derive from the Koine Greek title ''Christós'' (Χριστός), a translation of the Biblical Hebrew term '' mashiach'' (מָשִׁיחַ) (usually rendered as ''messiah'' in English). While there are diverse interpretations of Christianity which sometimes conflict, they are united in believing that Jesus has a unique significance. The term ''Christian'' used as an adjective is descriptive of anything associated with Christianity or Christian churches, or in a proverbial sense "all that is noble, and good, and Christ-like." It does not have a meaning of 'of Christ' or 'related or pertaining to Christ'. According to a 2011 Pew Research Center survey, there were 2.2 billion Christians around the world in 2010, up from about 600 million in 1910. Today, about 37% of all Christians live in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphipod
Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far described. They are mostly marine animals, but are found in almost all aquatic environments. Some 1,900 species live in fresh water, and the order also includes the terrestrial sandhoppers such as '' Talitrus saltator''. Etymology and names The name ''Amphipoda'' comes, via New Latin ', from the Greek roots 'on both/all sides' and 'foot'. This contrasts with the related Isopoda, which have a single kind of thoracic leg. Particularly among anglers, amphipods are known as ''freshwater shrimp'', ''scuds'', or ''sideswimmers''. Description Anatomy The body of an amphipod is divided into 13 segments, which can be grouped into a head, a thorax and an abdomen. The head is fused to the thorax, and bears two pairs of antennae and one pair o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Shelf
An ice shelf is a large floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto the ocean surface. Ice shelves are only found in Antarctica, Greenland, Northern Canada, and the Russian Arctic. The boundary between the floating ice shelf and the anchor ice (resting on bedrock) that feeds it is the grounding line. The thickness of ice shelves can range from about to . In contrast, sea ice is formed on water, is much thinner (typically less than ), and forms throughout the Arctic Ocean. It is also found in the Southern Ocean around the continent of Antarctica. The movement of ice shelves is principally driven by gravity-induced pressure from the grounded ice. That flow continually moves ice from the grounding line to the seaward front of the shelf. In steady state, about half of Antarctica's ice shelf mass is lost to basal melt and half is lost to calving, but the relative importance of each process varies significantly between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grounding Line
Marine ice sheet instability (MISI) describes the potential for ice sheets grounded below sea level to destabilize in a runaway fashion. The mechanism was first proposed in the 1970s by Johannes Weertman and was quickly identified as a means by which even gradual anthropogenic warming could lead to relatively rapid sea level rise. In Antarctica, the West Antarctic Ice Sheet, the Aurora Subglacial Basin, and the Wilkes Basin are each grounded below sea level and are inherently subject to MISI. General The term ''marine ice sheet'' describes an ice sheet whose base rests on ground below sea level, and ''marine ice sheet instability'' describes the inherent precarious nature of marine ice sheets due to Archimedes' principle. Because seawater is denser than ice, marine ice sheets can only remain stable where the ice is thick enough for its mass to exceed the mass of the seawater displaced by the ice. In other words, wherever ice exists below sea level, it is held in place only by the we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Whillans
Lake Whillans is a subglacial lake in Antarctica. The lake is located under the Whillans Ice Stream at the southeastern edge of the Ross Ice Shelf in the west of the continent. The lake surface is beneath the surface of the ice and the lake covers an estimated area of . Lake depths measured thus far have been around . Its temperature is −0.49 °C, below 0 °C because of the high pressure. Lake Whillans, like the Whillans Ice Stream, is named for Ohio State University glaciologist Dr. Ian Whillans. Discovery The lake was first described in 2007 by Helen Fricker, a glaciologist at the Scripps Institution of Oceanography. Satellite laser altimeter data from NASA's ICESat had revealed the ice at that location rising and falling, leading her team to conclude the presence of the lake. Research On 28 January 2013, the Whillans Ice Stream Subglacial Access Research Drilling (WISSARD) team announced that they had reached the lake surface having drilled through the ice abo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ICESat
ICESat (Ice, Cloud, and land Elevation Satellite) was a NASA satellite mission for measuring ice sheet mass balance, cloud and aerosol heights, as well as land topography and vegetation characteristics. It operated as part of NASA's Earth Observing System (EOS). ICESat was launched 13 January 2003 on a Delta II launch vehicle from Vandenberg Air Force Base in California into a near-circular, near-polar orbit with an altitude of approximately . It operated for seven years before being retired in February 2010, after its scientific payload shut down and scientists were unable to restart it. The ICESat mission was designed to provide elevation data needed to determine ice sheet mass balance as well as cloud property information, especially for stratospheric clouds common over polar areas. It provides topography and vegetation data around the globe, in addition to the polar-specific coverage over the Greenland and Antarctic ice sheets. The satellite was found useful in assessing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Antarctic Program
The United States Antarctic Program (or USAP; formerly known as the United States Antarctic Research Program or USARP and the United States Antarctic Service or USAS) is an organization of the United States government which has presence in the Antarctica continent. Founded in 1959, the USAP manages all U.S. scientific research and related logistics in Antarctica as well as aboard ships in the Southern Ocean. United States Antarctic Program The United States established the U.S. Antarctic Research Program (USARP) in 1959—the name was later changed to the U.S. Antarctic Program—immediately following the success of the International Geophysical Year (IGY). Today, the National Science Foundation (NSF) has a Presidential Mandate to manage the United States Antarctic Program, through which it operates three year-round research stations and two research vessels, coordinates all U.S. science on the southernmost continent, and works with other federal agencies, the U.S. military, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Antarctic Sun
''The Antarctic Sun'' is an online newspaper with "News about the United States Antarctic Program, USAP, the Ice, and the People." It is funded by the National Science Foundation (contract no. NSFDACS1219442) by its prime civilian contractor, Leidos Antarctic Support Contract. The online publication has been covering cutting edge science for the National Science Foundation since 1997–1998 austral summer, though it can trace its history back to the 1950s when the U.S. Navy ran logistics for the USAP. From the austral summer of 1997–98 to 2006–07, ''The Antarctic Sun'' has been produced at McMurdo Station between the months of October and February. Since October 2007, it has been a year-round news website managed out of the Denver, Colorado area. The website covers both science and features. The former includes biology, glaciology, geology, astrophysics and oceanography, among others. Features include USAP operations, Antarctic history, and profiles on people. Since 2016, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australia
Australia, officially the Commonwealth of Australia, is a sovereign ''Sovereign'' is a title which can be applied to the highest leader in various categories. The word is borrowed from Old French , which is ultimately derived from the Latin , meaning 'above'. The roles of a sovereign vary from monarch, ruler or ... country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by area in Oceania and the world's sixth-largest country. Australia is the oldest, flattest, and driest inhabited continent, with the least fertile soils. It is a megadiverse country, and its size gives it a wide variety of landscapes and climates, with deserts in the centre, tropical Forests of Australia, rainforests in the north-east, and List of mountains in Australia, mountain ranges in the south-east. The ancestors of Aboriginal Australians began arriving from south east Asia approx ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismographs
A seismometer is an instrument that responds to ground noises and shaking such as caused by earthquakes, Types of volcanic eruptions, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The output of such a device—formerly recorded on paper (see picture) or film, now recorded and processed digitally—is a seismogram. Such data is used to locate and characterize earthquakes, and to study the Earth's internal structure. Basic principles A simple seismometer, sensitive to up-down motions of the Earth, is like a weight hanging from a spring, both suspended from a frame that moves along with any motion detected. The relative motion between the weight (called the mass) and the frame provides a measurement of the vertical ground motion. A rotating drum is attached to the frame and a pen is attached to the weight, thus recording any ground motion in a seismogram. Any movement from the ground moves the fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
