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Permafrost
Permafrost () is soil or underwater sediment which continuously remains below for two years or more; the oldest permafrost has been continuously frozen for around 700,000 years. Whilst the shallowest permafrost has a vertical extent of below a meter (3 ft), the deepest is greater than . Similarly, the area of individual permafrost zones may be limited to narrow mountain summits or extend across vast Arctic regions. The ground beneath glaciers and ice sheets is not usually defined as permafrost, so on land, permafrost is generally located beneath a so-called active layer of soil which freezes and thaws depending on the season. Around 15% of the Northern Hemisphere or 11% of the global surface is underlain by permafrost, covering a total area of around . This includes large areas of Alaska, Canada, Greenland, and Siberia. It is also located in high mountain regions, with the Tibetan Plateau being a prominent example. Only a minority of permafrost exists in the Southern Hemi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Permafrost Association
The International Permafrost Association (IPA), founded in 1983, is an international professional body formed to foster the dissemination of knowledge concerning permafrost and to promote cooperation among individuals and national or international organisations engaged in Scientific method, scientific investigation and engineering work related to permafrost and seasonally frozen ground. The IPA became an Affiliated Organisation of the International Union of Geological Sciences in July 1989. The Association’s primary responsibilities are to convene International Permafrost Conferences, undertake special projects such as preparing databases, maps, Bibliography, bibliographies, and glossaries, and coordinate international field programmes and networks. The International Conference On Permafrost (ICOP) is regularly held since 1965. International Conference on Permafrost (ICOP) The first International conference (ICOP) was held at West Lafayette, Indiana, United States, in 1963, fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
