Journal of Geophysical Research, Vol. 109, F04007, doi:10.1029/2003JF000045, 2004
W. Abdalati (NASA Goddard Space Flight Center, Greenbelt, Maryland, USA); W. Krabill (Wallops Flight Facility, NASA Goddard Space Flight Center, Wallops Island, Virginia, USA); E. Frederick, S. Manizade, C. Martin, J. Sonntag, R. Swift, R. Thomas, and J. Yungel (EG&G, Wallops Flight Facility, NASA Goddard Space Flight Center, Wallops Island, Virginia, USA); R. Koerner (Geological Survey of Canada, Ottawa, Ontario, Canada)
Precise repeat airborne laser surveys were conducted over the major ice caps in the Canadian Arctic Archipelago in the spring of 1995 and 2000 in order to measure elevation changes in the region. Our measurements reveal thinning at lower elevations (below 1600 m) on most of the ice caps and glaciers but either very little change or thickening at higher elevations in the ice cap accumulation zones. Recent increases in precipitation in the area can account for the slight thickening where it was observed but not for the thinning at lower elevations. For the northern ice caps on the Queen Elizabeth Islands, thinning was generally <0.5>−1, which is consistent with what would be expected from the warm temperature anomalies in the region for the 5 year period between surveys, and appears to be a continuation of a trend that began in the mid-1980s. Farther south, however, on the Barnes and Penny ice caps on Baffin Island, this thinning was much more pronounced at over 1 m yr−1 in the lower elevations. Here temperature anomalies were very small, and the thinning at low elevations far exceeds any associated enhanced ablation. The observations on Barnes, and perhaps Penny, are consistent with the idea that the observed thinning is part of a much longer term deglaciation, as has been previously suggested for Barnes ice cap. On the basis of the regional relationships between elevation and elevation change in our data, the 1995–2000 mass balance for the archipelago is estimated to be −25 km3 yr−1 of ice, which corresponds to a sea level increase of 0.064 mm yr−1. This places it among the more significant sources of eustatic sea level rise, though not as substantial as the Greenland ice sheet, Alaskan glaciers, or the Patagonian ice fields.
Received 17 April 2003; accepted 8 September 2004; published 20 November 2004.
Keywords: ice caps, Arctic, mass balance
Index Terms: 1640 Global Change: Remote sensing; 1699 Global Change: General or miscellaneous; 1827 Hydrology: Glaciology (1863); 1863 Hydrology: Snow and ice (1827).
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Citation: (2004), Elevation changes of ice caps in the Canadian Arctic Archipelago, J. Geophys. Res., 109, F04007, doi:10.1029/2003JF000045.
Copyright 2004 by the American Geophysical Union.
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Combining ICESat and Aircraft Laser Altimetry Observations to Examine Recent Changes in Canadian Ice Caps
| Authors: | Abdalati, W.; Krabill, W.; Thomas, R.; Golder, J.; Frederick, E.; Manizade, S.; Martin, C. | |
| Affiliation: | AA(NASA Goddard Space Flight Center, Oceans and Ice Branch, Greenbelt, MD 20771 United States ; | |
| Publication: | American Geophysical Union, Fall Meeting 2004, abstract #C22A-02 | |
| Publication Date: | 12/2004 | |
| Origin: | AGU | |
| AGU Keywords: | 1699 General or miscellaneous, 1827 Glaciology (1863), 1863 Snow and ice (1827), 1640 Remote sensing | |
| Bibliographic Code: | 2004AGUFM.C22A..02A |
Abstract
Precise repeat airborne laser surveys were conducted over the major ice caps in the Canadian Arctic Archipelago during the spring of 1995 and 2000 to measure elevation changes in the region. Our observations reveal thinning at lower elevations (below 1600 m) on most of the ice caps and glaciers, but either very little change or thickening at higher elevations in the ice cap accumulation zones. The behavior of the ice caps in the north on the Queen Elizabeth Islands can be explained by recent temperature and precipitation anomalies, but this is not the case for the more southern ice caps on Baffin Island, which appear to be still shrinking in response to the Little Ice Age. The regional characteristics of elevation change as a function of elevation enables an assessment of the Canadian ice caps' contribution to sea level during the 1995-2000 time period. Our estimates place them among the more significant sources of eustatic sea level rise, though they are not as substantial as Greenland ice sheet, Alaskan glaciers, or the Patagonian ice fields. The spring 2004 campaign of the Ice Cloud and land Elevation Satellite (ICESat) mission provides a means of examining the character of changes since 2000. Comparisons between the ICESat data and the earlier aircraft campaigns where the ICESat ground tracks intersect the aircraft flight lines reveal significant changes in ice cap behavior between the late 1990s and the last four years. The results of these comparisons will be discussed along with the differences in the 1995-2000 and 2000-2004 climate conditions that affect the mass balance and elevation characteristics in those time periods.Link: http://adsabs.harvard.edu/abs/2004AGUFM.C22A..02A
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Effects of Climate Change on Baffin Island's Glaciers
interactions between ocean, atmosphere, and sea ice are expected to
amplify the effects of climate change" (Cubasch et al., 2001).
Holocene climate change in the Eastern Canadian Arctic has been influences by 3 factors: (1) the impact on atmospheric circulation by the waning Laurentide Ice Sheet (2) the steady decrease in summer solar insolation as regular changes in the Earth’s orbit diminished Northern Hemisphere seasonality and (3) changes in the balance between relatively warm, salty Atlantic water and the outflow of cold, low-salinity surface water from the Arctic Ocean. (Miller et al. 2005) Baffin Island’s glacial features have been affected by the warming trend experienced in the Holocene. At the peak of the last glacial maximum, warm based outlet glaciers occupied most fiords and sounds, but significant portions of Baffin Island were covered by cold based ice. By the beginning of the Holocene, the Eastern Canadian Arctic had warmed enough that most glaciers were warm based and deglaciation can deciphered from moraines, ice-con-tact deposits and from sediment cores taken. (Miller et al. 2005).
The advance and retreat of glaciers have long been understood to be tied to climate change (Ahlmann, 1953 in Bell and Jacobs, 1997).
Throughout the islands in Nunavut, evidences suggest recent neoglacial events that ended in the latter part of the 19th century (Bell and Jacobs, 1997). Glaciological data from the 20th century indicate a renewed glacial retreat from recent terminal moraines (Bell and Jacobs, 1997). The mass balance of glaciers in the area has shown be most influenced by summer near-surface air temperature, followed by winter precipitation (Johannesson et al., 1995 in Bell and Jacobs, 1997). Glacier studies completed in Nunavut, for example, of Boas in 1975, the Grinnell in 1956 and the White (Axel Heiberg) in 1995 showed that one warm summer can melt the net accumulation from a number of successive positive mass balance years (Bell and Jacobs, 1997). This is especially of interest under the current global warming trend.
In 1992, using glaciers from a wide range of climatic regimes, Oerlemans and Fortuin examined the sensitivities of glaciers and small ice caps to global warming (Bell and Jacobs, 1997). They found that under the condition of a uniform 1 K warming, the glacier mass balance will be lowered by 0.4 m/a and this corresponds to an increase of 0.58 mm/a in sea level (Bell and Jacobs, 1997).
Due to the logistic problems associated with completing research in remote sites, continuous field glacier monitoring in the High Arctic is limited to only a few glaciers, mostly confined to the Queen Elizabeth Islands (Bell and Jacobs, 1997). Bell and Jacobs (1997) suggests that Canada can adopt the data collection method used by Iceland, there, the Icelandic glacier observation program train laypeople living near glaciers how to measure and observe glacial patterns (Bell and Jacobs, 1997). In addition, with the recent advancement of satellite imagery, data is becoming more readily available.
From the 1960s to the 1990s, Baffin Island experienced a general cooling trend rather than a global warming trend like elsewhere in Nunavut (Bell and Jacobs, 1997). If this pattern continues, the resulting effects it is still uncertain.
rates than more northernly ice caps (Abdalati et al., 2004).
1960-1993. JJA stands for June, July, August (Bell and Jacobs, 1997).
Ice Caps on Baffin Island Include:
Barnes Ice Cap Grinnell Ice Cap Penny Ice Cap Terra Nivea Ice Cap
Glacial features in Cumberland Peninsula Include:
Boas Glacier Caribou Glacier Coronation Glacier Fork Beard Glacier Highway Glacier
Penny Ice Cap Tumbling Glacier
Glacial features in Hall Peninsula Include:
Grinnell Ice Cap
Glacial features in Meta Incognita Peninsula Include:
Terra Nivea Ice Cap
Additional Links:
Decade Glacier Effects of Climate Change on Baffin References
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