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Devon Ice Cap
The Devon Ice Cap is an ice cap on eastern Devon Island, Nunavut, Canada, covering an area of over . The highest point on Devon Island is found at the summit of the ice cap, with an elevation of . The ice cap has a maximum thickness of , and has been steadily shrinking since 1985. The first ascent of the Devon Ice Cap was by Alfred Herbert Joy and his Inuit companions in 1926. Geology The Devon Ice Cap and the Agassiz Ice Cap on the neighboring Ellesmere Island are two of the largest ice caps in the Arctic Cordillera in the Canadian Arctic, and consist of a substantial fraction of ice not locked away in the Antarctic and Greenland ice sheets. As such, should the entire Devon Ice Cap melt due to global warming, the ice will contribute approximately 1 centimeter to global sea level rise. The Devon Ice Cap has a dome-like structure and a maximum elevation of 1921 m above sea level at its summit, and the maximum ice thickness is 880 m. There are two distinct regions in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Ultras Of Canada
The following sortable table comprises the 150 most topographically prominent mountain peaks of Canada. The summit of a mountain or hill may be measured in three principal ways: #The topographic elevation of a summit measures the height of the summit above a geodetic sea level.If the elevation or prominence of a summit is calculated as a range of values, the arithmetic mean is shown. #The topographic prominence of a summit is a measure of how high the summit rises above its surroundings.The topographic prominence of a summit is the topographic elevation difference between the summit and its highest or key col to a higher summit. The summit may be near its key col or quite far away. The key col for Denali in Alaska is the Isthmus of Rivas in Nicaragua, away. #The topographic isolation (or radius of dominance) of a summit measures how far the summit lies from its nearest point of equal elevation.The topographic isolation of a summit is the great-circle distance to its near ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenland Ice Sheet
The Greenland ice sheet ( da, Grønlands indlandsis, kl, Sermersuaq) is a vast body of ice covering , roughly near 80% of the surface of Greenland. It is sometimes referred to as an ice cap, or under the term ''inland ice'', or its Danish equivalent, ''indlandsis''. An acronym, GIS, is frequently used in the scientific literature. It is the second largest ice body in the world, after the Antarctic ice sheet. The ice sheet is almost long in a north–south direction, and its greatest width is at a latitude of 77°N, near its northern margin. The average thickness is about and over at its thickest point. In addition to the large ice sheet, smaller ice caps (such as Maniitsoq and Flade Isblink) as well as glaciers, cover between around the periphery. The Greenland ice sheet is adversely affected by climate change. It is more vulnerable to climate change than the Antarctic ice sheet because of its position in the Arctic, where it is subject to the regional amplificatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Caps Of Canada
Ice is water frozen into a solid state, typically forming at or below temperatures of 0 degrees Celsius or Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaque bluish-white color. In the Solar System, ice is abundant and occurs naturally from as close to the Sun as Mercury to as far away as the Oort cloud objects. Beyond the Solar System, it occurs as interstellar ice. It is abundant on Earth's surfaceparticularly in the polar regions and above the snow lineand, as a common form of precipitation and deposition, plays a key role in Earth's water cycle and climate. It falls as snowflakes and hail or occurs as frost, icicles or ice spikes and aggregates from snow as glaciers and ice sheets. Ice exhibits at least eighteen phases ( packing geometries), depending on temperature and pressure. When water is cooled rapidly (quenching), up to three types of amorphous ice can form depending on its h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Ultras Of North America
The following sortable tables comprise the most topographically prominent mountain peaks of greater North America. Each of these 353 summits has at least of topographic prominence. This article defines greater North America as the portion of the continental landmass of the Americas extending westward and northward from the Isthmus of Panama plus the islands surrounding that landmass. This article defines the islands of North America to include the coastal islands of North America, the islands of the Caribbean Sea, the Lucayan Archipelago, the Bermuda Islands, the Islands of Greenland ( Kalaallit Nunaat), the islands of Northern Canada, the islands of Alaska, and the islands of the northeastern Pacific Ocean. The Hawaiian Islands are not included because they are considered part of Oceania. Topographic elevation is the vertical distance above the reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface. The topographic prom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retreat Of Glaciers Since 1850
The retreat of glaciers since 1850 affects the availability of fresh water for irrigation and domestic use, mountain recreation, animals and plants that depend on glacier-melt, and, in the longer term, the level of the oceans. Deglaciation occurs naturally at the end of ice ages, but glaciologists find the current glacier retreat is accelerated by the measured increase of atmospheric greenhouse gases—an effect of climate change. Mid-latitude mountain ranges such as the Himalayas, Rockies, Alps, Cascades, Southern Alps, and the southern Andes, as well as isolated tropical summits such as Mount Kilimanjaro in Africa, are showing some of the largest proportionate glacial losses. Excluding peripheral glaciers of ice sheets, the total cumulated global glacial losses over the 26 year period from 1993–2018 were likely 5500 gigatons, or 210 gigatons per yr.Fox-Kemper, B., H.T. Hewitt, C. Xiao, G. Aðalgeirsdóttir, S.S. Drijfhout, T.L. Edwards, N.R. Golledge, M. Hemer, R.E. Ko ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subglacial Channel
A subglacial meltwater channel is a channel beneath an ice mass, such as ice sheets and valley glaciers, roughly parallel to the main ice flow direction. These meltwater channels can have different sizes, ranging from very small channels of a metre deep and wide to big valleys which can be up to a kilometre wide. The dimensions of these channels are regulated by several factors: water temperature, meltwater volume, debris content in the water, ice wall closure rates (governed by the ice thickness) and squeezing of fluidized sediment. In the glaciological literature three forms of subglacial meltwater channels are commonly mentioned. R-channels The first type of channel is the ''R-channel'' after Hans Röthlisberger who initiated work on water pressures in tubes under glaciers. These are semi-circular channels cut upward into the ice. The balance between channel enlargement by viscous heating and closure by ice deformation when the channels are water-filled reflects their size and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioglaciology
Radioglaciology is the study of glaciers, ice sheets, ice caps and icy moons using ice penetrating radar. It employs a geophysical method similar to ground-penetrating radar and typically operates at frequencies in the MF, HF, VHF and UHF portions of the radio spectrum. This technique is also commonly referred to as "Ice Penetrating Radar (IPR)" or "Radio Echo Sounding (RES)". Glaciers are particularly well suited to investigation by radar because the conductivity, imaginary part of the permittivity, and the dielectric absorption of ice are small at radio frequencies resulting in low loss tangent, skin depth, and attenuation values. This allows echoes from the base of the ice sheet to be detected through ice thicknesses greater than 4 km. The subsurface observation of ice masses using radio waves has been an integral and evolving geophysical technique in glaciology for over half a century. Its most widespread uses have been the measurement of ice thickness, subg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacier Morphology
Glacier morphology, or the form a glacier takes, is influenced by temperature, precipitation, topography, and other factors. The goal of glacial morphology is to gain a better understanding of glaciated landscapes and the way they are shaped. Types of glaciers can range from massive ice sheets, such as the Greenland ice sheet, to small cirque glaciers found perched on mountain tops. Glaciers can be grouped into two main categories: * Ice flow is constrained by the underlying bedrock topography * Ice flow is unrestricted by surrounding topography Unconstrained Glaciers Ice sheets and ice caps Ice sheets and ice caps cover the largest areas of land in comparison to other glaciers, and their ice is unconstrained by the underlying topography. They are the largest glacial ice formations and hold the vast majority of the world's fresh water. Ice sheets Ice sheets are the largest form of glacial formation. They are continent sized ice masses that span areas over . They are dome s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Level Rise
Globally, sea levels are rising due to human-caused climate change. Between 1901 and 2018, the globally averaged sea level rose by , or 1–2 mm per year on average.IPCC, 2019Summary for Policymakers InIPCC Special Report on the Ocean and Cryosphere in a Changing Climate .-O. Pörtner, D.C. Roberts, V. Masson-Delmotte, P. Zhai, M. Tignor, E. Poloczanska, K. Mintenbeck, A. Alegría, M. Nicolai, A. Okem, J. Petzold, B. Rama, N.M. Weyer (eds.) Cambridge University Press, Cambridge, UK and New York, NY, USA. https://doi.org/10.1017/9781009157964.001. This rate is accelerating, with sea levels now rising by 3.7 mm per year. Climate scientists expect further acceleration during the 21st century. Climate change heats (and therefore expands) the ocean and melts land-based ice sheets and glaciers. Between 1993 and 2018, the thermal expansion of water contributed 42% to sea level rise; melting of temperate glaciers, 21%; Greenland, 15%; and Antarctica, 8%. Over the next ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Ice Sheet
The Antarctic ice sheet is one of the two polar ice caps of Earth. It covers about 98% of the Antarctic continent and is the largest single mass of ice on Earth, with an average thickness of over 2 kilometers. It covers an area of almost and contains of ice. A cubic kilometer of ice weighs approximately 0.92 metric gigatonnes, meaning that the ice sheet weighs ~24,380,000 gigatonnes. It holds approximately 61% of all fresh water on Earth, equivalent to about 58 meters of sea level rise if all the ice were above sea level. In East Antarctica, the ice sheet rests on a major land mass, while in West Antarctica the bed can extend to more than 2,500 m below sea level. Satellite measurements by NASA indicate a still increasing sheet thickness above the continent, outweighing the losses at the edge. The reasons for this are not fully understood, but suggestions include the climatic effects on ocean and atmospheric circulation of the ozone hole, and/or cooler ocean surface temp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Most Isolated Mountain Peaks Of Canada
The following sortable table comprises the 150 most topographically isolated mountain peaks of Canada with at least of topographic prominence.This article defines a significant summit as a summit with at least of topographic prominence, and a major summit as a summit with at least of topographic prominence. All summits in this article have at least 500 meters of topographic prominence. An ultra-prominent summit is a summit with at least of topographic prominence. The summit of a mountain or hill may be measured in three principal ways: #The topographic elevation of a summit measures the height of the summit above a geodetic sea level.If the elevation or prominence of a summit is calculated as a range of values, the arithmetic mean is shown. #The topographic prominence of a summit is a measure of how high the summit rises above its surroundings.The topographic prominence of a summit is the topographic elevation difference between the summit and its highest or key c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arctic Cordillera
The Arctic Cordillera is a terrestrial ecozone in northern Canada characterized by a vast, deeply dissected chain of mountain ranges extending along the northeastern flank of the Canadian Arctic Archipelago from Ellesmere Island to the northeasternmost part of the Labrador Peninsula in northern Labrador and northern Quebec, Canada. It spans most of the eastern coast of Nunavut with high glaciated peaks rising through ice fields and some of Canada's largest ice caps, including the Penny Ice Cap on Baffin Island. It is bounded to the east by Baffin Bay, Davis Strait and the Labrador Sea while its northern portion is bounded by the Arctic Ocean. Overview The range is mostly located in Nunavut but extends southeast into the northernmost tip of Labrador and northeastern Quebec. The system is divided into a series of ranges, with mountains reaching heights of more than . The highest is Barbeau Peak on Ellesmere Island at , which is the highest point in eastern North America. The sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
