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25-876: Hercules Dome ( 86°S 105°W  /  86°S 105°W  / -86; -105 ) is a large ice dome between the Thiel Mountains and the Horlick Mountains in Antarctica. The feature was first mapped by the United States Geological Survey from U.S. Navy aerial photographs taken 1959–60. It was further delineated by the Scott Polar Research Institute – National Science Foundation – Technical University of Denmark airborne aerial radio echo sounding program, 1967–79, and named after

50-504: A 95 ± 29  mm rise in global sea levels until they reach equilibrium. However, environmental conditions have worsened and are predicted to continue to worsen in the future. Given that the rate of melting will accelerate, and by using mathematical models to predict future climate patterns, the actual contribution of ice caps to rising sea levels is expected to be more than double from initial estimates. High-latitude regions covered in ice, though strictly not an ice cap (since they exceed

75-432: A body of ice to be termed a polar ice cap, nor any geological requirement for it to be over land, but only that it must be a body of solid phase matter in the polar region . This causes the term "polar ice cap" to be something of a misnomer, as the term ice cap itself is applied more narrowly to bodies that are over land, and cover less than 50,000 km : larger bodies are referred to as ice sheets . The composition of

100-527: A minimum Arctic sea ice extent somewhat above that of 2007. At other times of the year the ice extent is still sometimes near the 1979–2000 average, as in April 2010, by the data from the National Snow and Ice Data Center. Still, between these same years, the overall average ice coverage appears to have declined from 8 million km to 5 million km . Earth's south polar land mass, Antarctica ,

125-575: A result of the previous melting of the ice sheet, by increasing the freezing point of the seawater. The current rate of decline of the ice caps has caused many investigations and discoveries on glacier dynamics and their influence on the world's climate. In the early 1950s, scientists and engineers from the US Army began drilling into polar ice caps for geological insight. These studies resulted in "nearly forty years of research experience and achievements in deep polar ice core drillings... and established

150-499: A senior research scientist at NASA, found that the "rate of warming in the Arctic over the last 20 years is eight times the rate of warming over the last 100 years." In September 2012, sea ice reached its smallest size ever. Journalist John Vidal stated that sea ice is "700,000 sq km below the previous minimum of 4.17m sq km set in 2007". In August 2013, Arctic sea ice extent averaged 6.09m km , which represents 1.13 million km below

175-493: Is Biscayarfonna in Svalbard . Hypothetical runaway greenhouse state Tropical temperatures may reach poles Global climate during an ice age Earth's surface entirely or nearly frozen over Polar ice cap A polar ice cap or polar cap is a high- latitude region of a planet , dwarf planet , or natural satellite that is covered in ice . There are no requirements with respect to size or composition for

200-544: Is covered by the Antarctic ice sheet . It covers an area of about 14.6 million km and contains between 25 and 30 million km of ice. Around 70% of the fresh water on Earth is contained in this ice sheet. Data from the National Snow and Ice Data Center shows that the sea ice coverage of Antarctica has a slightly positive trend over the last three decades (1979–2009). Over the past several decades, Earth's polar ice caps have gained significant attention because of

225-596: Is usually about 1 meter thick. The area covered by sea ice ranges between 9 and 12 million km . In addition, the Greenland ice sheet covers about 1.71 million km and contains about 2.6 million km of ice. When the ice breaks off (calves) it forms icebergs scattered around the northern Atlantic. According to the National Snow and Ice Data Center , "since 1979, winter Arctic ice extent has decreased about 4.2 percent per decade". Both 2008 and 2009 had

250-626: The Lockheed LC-130 Hercules aircraft which was used on all echo sounding flights from 1969. The dome is notable for its unusually high number of subglacial lakes . [REDACTED]  This article incorporates public domain material from "Hercules Dome" . Geographic Names Information System . United States Geological Survey . This Marie Byrd Land location article is a stub . You can help Misplaced Pages by expanding it . Ice cap Ice caps are not constrained by topographical features (i.e., they will lie over

275-612: The 1981–2010 average for that month. In addition to Earth, the planet Mars also has polar ice caps. They consist of primarily water-ice with a few percent dust. Frozen carbon dioxide makes up a small permanent portion of the Planum Australe or the South Polar Layered Deposits. In both hemispheres a seasonal carbon dioxide frost deposits in the winter and sublimates during the spring. Data collected in 2001 from NASA missions to Mars show that

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300-540: The alarming decrease in land and sea ice. NASA reports that since the late 1970s, the Arctic has lost an average of 20,800 square miles (53,900 square kilometres) of sea ice per year while the Antarctic has gained an average of 7,300 square miles (18,900 km ) of sea ice per year. At the same time, the Arctic has been losing around 50 cubic kilometres (gigatons) of land ice per year, almost entirely from Greenland's 2.6 million gigaton sheet. On 19 September 2014, for

325-488: The entire ice cap and will follow the downward slopes of the land. Ice caps have been used as indicators of global warming, as increasing temperatures cause ice caps to melt and lose mass faster than they accumulate mass. Ice cap size can be monitored through different remote-sensing methods such as aircraft and satellite data. Ice caps accumulate snow on their upper surfaces, and ablate snow on their lower surfaces. An ice cap in equilibrium accumulates and ablates snow at

350-414: The first time since 1979, Antarctic sea ice extent exceeded 7.72 million square miles (20 million square kilometres), according to the National Snow and Ice Data Center . The ice extent stayed above this benchmark extent for several days. The average maximum extent between 1981 and 2010 was 7.23 million square miles (18.72 million square kilometres). The single-day maximum extent in 2014

375-411: The fundamental drilling technology for retrieving deep ice cores for climatologic archives." Polar ice caps have been used to track current climate patterns but also patterns over the past several thousands years from the traces of CO 2 and CH 4 found trapped in the ice. In the past decade, polar ice caps have shown their most rapid decline in size with no true sign of recovery. Josefino Comiso,

400-564: The glacier's retreat. Many lakes, such as the Great Lakes in North America, as well as numerous valleys have been formed by glacial action over hundreds of thousands of years. The Antarctic and Greenland contain 99% of the ice volume on earth, about 33 million cubic kilometres (7.9 million cubic miles) of total ice mass. Ice caps are formed when snow is deposited during the cold season and fails to completely melt during

425-402: The hot season. Over time, the snow builds up and becomes dense, well-bonded snow known as perennial firn . Finally, the air passages between snow particles close off and transforms into ice. The shape of an ice cap is determined by the landscape it lies on, as melting patterns can vary with terrain. For example, the lower portions of an ice cap are forced to flow outwards under the weight of

450-566: The ice caps takes place due to varied solar energy absorption as the planet or moon revolves around the Sun. Additionally, in geologic time scales, the ice caps may grow or shrink due to climate change. Earth's North Pole is covered by floating pack ice ( sea ice ) over the Arctic Ocean . Portions of the ice that do not melt seasonally can get very thick, up to 3–4 meters thick over large areas, with ridges up to 20 meters thick. One-year ice

475-445: The ice will vary. For example, Earth's polar caps are mainly water ice, whereas Mars 's polar ice caps are a mixture of solid carbon dioxide and water ice. Polar ice caps form because high-latitude regions receive less energy in the form of solar radiation from the Sun than equatorial regions, resulting in lower surface temperatures. Earth's polar caps have changed dramatically over the last 12,000 years. Seasonal variations of

500-461: The long term, the AAR of glaciers has been about 0.57. In contrast, data from the most recent years of 1997–2006 yields an AAR of only 0.44. In other words, glaciers and ice caps are accumulating less snow and are out of equilibrium, causing melting and contributing to sea level rises. Assuming the climate continues to be in the same state as it was in 2006, it is estimated that ice caps will contribute

525-461: The maximum area specified in the definition above), are called polar ice caps ; the usage of this designation is widespread in the mass media and arguably recognized by experts. Vatnajökull is an example of an ice cap in Iceland . Plateau glaciers are glaciers that overlie a generally flat highland area. Usually, the ice overflows as hanging glaciers in the lower parts of the edges. An example

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550-423: The same rate. The AAR is the ratio between the accumulation area and the total area of the ice cap, which is used to indicate the health of the glacier. Depending on their shape and mass, healthy glaciers in equilibrium typically have an AAR of approximately 0.4 to 0.8. The AAR is impacted by environmental conditions such as temperature and precipitation. Data from 86 mountain glaciers and ice caps shows that over

575-539: The southern residual ice cap undergoes sublimation inter-annually. The most widely accepted explanation is that fluctuations in the planet's orbit are causing the changes. On 29 April 2015, NASA stated that its New Horizons missions had discovered a feature thought to be a polar ice cap on the dwarf planet Pluto . The probe's flyby of Pluto in July 2015 allowed the Alice ultraviolet imaging spectrometer to confirm that

600-472: The top of mountains). By contrast, ice masses of similar size that are constrained by topographical features are known as ice fields . The dome of an ice cap is usually centred on the highest point of a massif . Ice flows away from this high point (the ice divide ) towards the ice cap's periphery. Ice caps significantly affect the geomorphology of the area they occupy. Plastic moulding, gouging and other glacial erosional features become present upon

625-472: Was reached on 20 Sep, according to NSIDC data, when the sea ice covered 7.78 million square miles (20.14 million square kilometres). The 2014 five-day average maximum was reached on 22 Sep, when sea ice covered 7.76 million square miles (20.11 million square kilometres), according to NSIDC . This increase could be due to the reduction in the salinity of the Antarctic Ocean as

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