Access

You are not currently logged in.

Access JSTOR through your library or other institution:

login

Log in through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Recent Climatic Fluctuations of the Canadian High Arctic and Their Significance for Glaciology

Raymond S. Bradley and John England
Arctic and Alpine Research
Vol. 10, No. 4 (Nov., 1978), pp. 715-731
DOI: 10.2307/1550739
Stable URL: http://www.jstor.org/stable/1550739
Page Count: 17
  • Read Online (Free)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Recent Climatic Fluctuations of the Canadian High Arctic and Their Significance for Glaciology
Preview not available

Abstract

Various measures of the character of ablation season conditions in the Canadian High Arctic (north of 74°N) are discussed based on an analysis of daily climatic data from Alert, Eureka, Isachsen, Resolute, and Thule. Melting degree day totals appear to be the most useful index of "summer warmth." An abrupt change in the summer climate of the region occurred around 1963/64. Various indices indicate a marked decrease in summer temperature after 1963. During the same period, annual precipitation in the north and northwest has increased. Glacier mass balance is strongly controlled by summer climate; in particular, annual melting degree day totals are highly correlated with long-term mass-balance records. This enabled mass balance on the northwest sector of the Devon Island ice cap to be reconstructed back to 1947/48. Cumulative mass losses on the Devon Island ice cap from 1947/48 to 1962/63 are estimated to be ∼3500 kg m-2. However, from 1963/64 to 1973/74 a total of <350 kg m-2 have been lost. Significant ice-cap growth is presently limited by low precipitation even when mean summer temperatures are very low; an occasional warm summer may therefore obliterate cumulative mass gains over many years. The post-1963 change in summer climate appears to be related to the massive increase of volcanic dust in the upper atmosphere, primarily due to the eruption of Mt. Agung (March 1963). Subsequent eruptions may have caused the cooler conditions to persist. Volcanic dust affects solar radiation receipts and perhaps also influences the general circulation. If the high volcanic dust levels of the 1960s are responsible for reduced mass losses on High Arctic glaciers and ice caps, it is probable that other periods with high atmospheric dust levels (e.g., 1750 to 1880) had summer temperatures at least as cold as the mid to late 1960s. Conversely, the period of very negative balance on the Devon Island ice cap from 1947 to 1963 was probably typical of the period back to 1920 when the atmosphere was relatively free of volcanic dust.

Page Thumbnails

  • Thumbnail: Page 
715
    715
  • Thumbnail: Page 
716
    716
  • Thumbnail: Page 
717
    717
  • Thumbnail: Page 
718
    718
  • Thumbnail: Page 
719
    719
  • Thumbnail: Page 
720
    720
  • Thumbnail: Page 
721
    721
  • Thumbnail: Page 
722
    722
  • Thumbnail: Page 
723
    723
  • Thumbnail: Page 
724
    724
  • Thumbnail: Page 
725
    725
  • Thumbnail: Page 
726
    726
  • Thumbnail: Page 
727
    727
  • Thumbnail: Page 
728
    728
  • Thumbnail: Page 
729
    729
  • Thumbnail: Page 
730
    730
  • Thumbnail: Page 
731
    731