HR: 0800h
AN: GC51A-1055    [Abstracts]
TI: Changes in Terrestrial Snow and Ice Following the Little Ice Age in the Queen Elizabeth Islands, Arctic Canada
AU: * Wolken, G
EM: gwolken@ualberta.ca
AF: Department of Earth and Atmospheric Sciences, University of Alberta, 1-26 Earth Sciences Building, Edmonton, AB T6G 2E3 Canada
AU: England, J
EM: John.England@ualberta.ca
AF: Department of Earth and Atmospheric Sciences, University of Alberta, 1-26 Earth Sciences Building, Edmonton, AB T6G 2E3 Canada
AU: Sharp, M
EM: Martin.Sharp@ualberta.ca
AF: Department of Earth and Atmospheric Sciences, University of Alberta, 1-26 Earth Sciences Building, Edmonton, AB T6G 2E3 Canada
AU: Bush, A
EM: Andrew.Bush@ualberta.ca
AF: Department of Earth and Atmospheric Sciences, University of Alberta, 1-26 Earth Sciences Building, Edmonton, AB T6G 2E3 Canada
AB: Climate change during the 20th and 21st centuries has resulted in extensive modification of polar regions; this trend is expected to continue as predicted temperature increases there exceed those elsewhere on the globe (IPCC, 2001). The instrumental temperature record in the Canadian High Arctic extends back only $\sim$55 years, therefore, it is essential to investigate other proxy records to determine variability over longer time scales. This will provide a more meaningful measure of natural variability and the longer record will serve as a reference against which modern and future conditions may be compared and modelled. A substantial reduction in terrestrial ice cover in the Queen Elizabeth Islands (QEI) following the Little Ice Age (LIA) ($\sim$1600 to 1900 AD), is indicated by widespread, light-toned patches of poorly vegetated terrain, extending back to the modern ice mass. These patches display abrupt outer margins (trimlines), which record the former position and maximum extent of perennial snow and ice, and in many cases, mark their former equilibrium-line altitude (ELA). Therefore, trimlines on a regional scale serve as an important proxy for measuring late Holocene environmental change and a means of estimating climatic change. Classification methods were employed with high-resolution multispectral imagery (ASTER and Landsat 5 and 7) to map trimlines and modern ice margins throughout the QEI, and 1959/60 ice outlines for the same area were obtained from the National Topographic Database (NTDB) (provided by Geomatics Canada). Results indicate reductions in terrestrial ice cover throughout the QEI ranging from $\sim$27 to 84% since the termination of the LIA. Regional patterns related to ice reduction and changes in the ELAs will be discussed, and initial estimates of temperature and precipitation changes will also be presented.
DE: 3349 Polar meteorology
DE: 3309 Climatology (1620)
DE: 1699 General or miscellaneous
DE: 1863 Snow and ice (1827)
SC: Global Climate Change [GC]
MN: 2004 AGU Fall Meeting