CGRG Bibliography of Canadian Geomorphology
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Author : Cawkwell, F.
Date : 2005.
Title : Environmental drivers of recent glaciological changes in the Queen Elizabeth Islands, Canada.
Publication : 35th Annual International Arctic Workshop. March 9-12, 2005. Timms Centre for the Arts, University of Alberta, Edmonton, Alberta, Canada.
Issue :
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Abstract
The Global Land Ice Measurements from Space (GLIMS) project is an international endeavour designed to monitor the world’s glaciers using satellite data to establish an inventory of land ice extent at the end of the 20th century. The Canadian Regional Centre, established at the University of Alberta in 2002, covers the glaciers and ice caps of the Queen Elizabeth Islands (QEI) in the Canadian High Arctic, the Yukon and the Cordillera. With an archive of several hundred ASTER and Landsat satellite images from the 1990s, accurate retrieval of the ice area in these regions can be undertaken, and compared with a collection of several thousand aerial photographs from the 1950s to quantify the areas and magnitude of change. In conjunction with additional data, such as surface elevation, sea ice extent and numerical reanalysis of climatic variables, these databases of contemporary and historic ice area are a valuable resource for studying the relationships between components of the cryospheric system and their inter-dependency. The Manson Icefield, located in the south-east of the QEI archipelago, lost 131 km2 ice, or 2.1 % of its total area between 1959 and 1999. However, there was not uniform loss with the Mittie Glacier advancing by at least 4 km and the surface becoming heavily crevassed 30 km upglacier from the terminus. Several other outlet glaciers on the Manson Icefield also show evidence of changes in flow regime over this period, and compared with other contiguous ice areas in the QEI, the number of outlet glaciers on the Manson Icefield displaying evidence of fast flow initiated in the second half of the twentieth century is statistically significant. Glacier morphometric parameters expressed in terms of a balance ratio and sensitivity index show a much lower relationship between basin form and ice area change on the Manson Icefield than on the neighbouring Devon Icecap. Numerical reanalysis data show an increase in mean June temperatures over the past 25 years, whilst the sea ice record from passive microwave data shows a decrease of up to 2 %a-1 along the eastern coast of the icefield where many of the tidewater glaciers terminate. By comparison, further north the Agassiz Icecap lost 1.4 % of its ice covered area over the same period (a total of 242 km2), during which time a summer temperature increase was also evident. A much smaller proportion of the ice area change on this icecap has originated from the localised movement of major glacier fronts, and there is a less polarised distribution in the flow orientation of glaciers showing significant change. There is also a lower than expected incidence of surging glaciers on the Agassiz Icecap, and unlike on the Manson Icefield not all the major glacier fronts extend to the sea. One suggestion that can be posited for the differences in behaviour between these two regions is the link between the mechanical influence exerted by sea ice and the initiation of surge activity, with subsequent feedback effects on the icefield dynamics.
Bibliography of Canadian Geomorphology