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AGU: Journal of Geophysical Research, Atmospheres

 

Keywords

  • ice core
  • melt
  • image analysis

Index Terms

  • Atmospheric Processes: Climate change and variability
  • Atmospheric Processes: Paleoclimatology
  • Cryosphere: Ice cores
  • Cryosphere: Polynas
  • Cryosphere: Instruments and techniques
Abstract
Cited By (2)
 

Abstract

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 113, D24120, 14 PP., 2008
doi:10.1029/2008JD011083

Stratigraphic analysis of an ice core from the Prince of Wales Icefield, Ellesmere Island, Arctic Canada, using digital image analysis: High-resolution density, past summer warmth reconstruction, and melt effect on ice core solid conductivity

Christophe Kinnard

Geological Survey of Canada, Natural Resources Canada, Ottawa, Ontario, Canada

Department of Geography, University of Ottawa, Ottawa, Ontario, Canada

Roy M. Koerner

Geological Survey of Canada, Natural Resources Canada, Ottawa, Ontario, Canada

Christian M. Zdanowicz

Geological Survey of Canada, Natural Resources Canada, Ottawa, Ontario, Canada

David A. Fisher

Geological Survey of Canada, Natural Resources Canada, Ottawa, Ontario, Canada

Jiancheng Zheng

Geological Survey of Canada, Natural Resources Canada, Ottawa, Ontario, Canada

Martin J. Sharp

Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, Canada

Lindsey Nicholson

Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, Canada

Bernard Lauriol

Department of Geography, University of Ottawa, Ottawa, Ontario, Canada

High-resolution (1 mm) stratigraphic information was derived from digital image analysis of an ice core from the Prince of Wales (POW) Icefield, Central Ellesmere Island, Canada. Following careful image processing, a profile of ice core transmitted light was derived from the greyscale images and used to reconstruct high-resolution density variations for the unfractured sections of the core. Images were further classified into infiltration and glacier ice using an automatic thresholding procedure, and were converted to a high-resolution melt percentage index. The mean annual melt percentage over the last 580 years was 9%, and melting occurred in 8 years out of 10. Melting obliterated most of the original depositional sequence, and seasonal density cycles were mostly unrecognizable. The ice core solid conductivity was greater and more variable in melt features than in glacier ice, owing to washout of strong acids by meltwater (elution) and chemical enrichment upon refreezing. This hindered the identification of acid volcanic layers and further compromised dating by annual layer counting. Comparison of the melt record with those from other Arctic ice caps shows that the melt-temperature relationship on POW Icefield is site-specific. We speculate that this is due to the peculiar position of the icefield, which rests on the periphery of the Baffin Bay maritime climate zone, and to the proximity of the North Open Water polynya, which controls snow accumulation variability on the icefield and affects the melt percentage index.

Received 2 September 2008; accepted 14 November 2008; published 31 December 2008.

Citation: Kinnard, C., R. M. Koerner, C. M. Zdanowicz, D. A. Fisher, J. Zheng, M. J. Sharp, L. Nicholson, and B. Lauriol (2008), Stratigraphic analysis of an ice core from the Prince of Wales Icefield, Ellesmere Island, Arctic Canada, using digital image analysis: High-resolution density, past summer warmth reconstruction, and melt effect on ice core solid conductivity, J. Geophys. Res., 113, D24120, doi:10.1029/2008JD011083.

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