Climate and Permafrost 59 Permafrost distribution along the Rocky Mountains in Alberta
Twenty-eight drill holes ranging from 15 to 150 m in depth have been instrumented with strings of thermistors and thermocouples at six study sites between Plateau Mountain and Jasper, south-west Alberta. Measurements are made every four weeks and indicate that the lower limit of continuous permafros...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.574.7388 http://pubs.aina.ucalgary.ca/cpc/cpc4-59.pdf |
| Summary: | Twenty-eight drill holes ranging from 15 to 150 m in depth have been instrumented with strings of thermistors and thermocouples at six study sites between Plateau Mountain and Jasper, south-west Alberta. Measurements are made every four weeks and indicate that the lower limit of continuous permafrost forms a dome-shape with its centre at Bow Summit, at 2575 m. The limit lies around 2130 m at Jasper and 2270 m at Plateau Mountain. This dome appears to be due to increased snowfall around the ice caps and glaciers, and there may be an inverse relationship between the elevation of the glaciation limit and that of the lower limit of continuous permafrost at a given latitude. In areas of low winter snowfall, the zone of discontinuous permafrost usually extends only 25 m in elevation below the lower limit of continuous permafrost but probably increases in altitudinal range as mean winter snowfall increases. Relict permafrost occurs at Plateau Mountain, which is the only site which shows no signs of overriding by Pleistocene glaciers. Even there, present-day heating and cooling waves extend downwards throughout the layers being studied. It is therefore suggested that the "zone of zero amplitude " be renamed the "zone of minimal amplitude " defined as being where the amplitude over a period of two years is less than 0.20°C. Des chapelets de thermistor et de thermocouples ont kt6 install & dans vingt-huit forages d'une pro-fondeur de 15 a 150 m en six emplacements entre le mont Plateau et Jasper dans le sud-ouest de 1'Al-berta. Des mesures effectukes toutes les quatre semaines indiquent que la limite infkrieure du pergdisol |
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