scholarly journals Accumulation on the Devon Island Ice Cap, Northwest Territories, Canada

1966 ◽  
Vol 6 (45) ◽  
pp. 383-392 ◽  
Author(s):  
R. M. Koerner

The pattern of accumulation on the Devon Island ice cap is described. There is an area of minimum accumulation encircling the highest part of the ice cap and 100–200 m. below it. Below this zone, accumulation gradually increases to a maximum near the ice-cap edge. The overall pattern is related to snow transport by katabatic winds. There is a regional accumulation pattern of high accumulation (ca. 40.0 cm. water equivalent) in the south-east part of the ice cap and an area of low accumulation (ca. 11 0 cm. water equivalent) in the north-west. This east-south-east to west-north-west accumulation gradient is related to cyclonic activity to the east in Baffin Bay, and it is probably intensified by the presence of open water in the same area.

1966 ◽  
Vol 6 (45) ◽  
pp. 383-392 ◽  
Author(s):  
R. M. Koerner

The pattern of accumulation on the Devon Island ice cap is described. There is an area of minimum accumulation encircling the highest part of the ice cap and 100–200 m. below it. Below this zone, accumulation gradually increases to a maximum near the ice-cap edge. The overall pattern is related to snow transport by katabatic winds. There is a regional accumulation pattern of high accumulation (ca. 40.0 cm. water equivalent) in the south-east part of the ice cap and an area of low accumulation (ca. 11 0 cm. water equivalent) in the north-west. This east-south-east to west-north-west accumulation gradient is related to cyclonic activity to the east in Baffin Bay, and it is probably intensified by the presence of open water in the same area.


1970 ◽  
Vol 9 (57) ◽  
pp. 325-336 ◽  
Author(s):  
R.M. Koerner

Methods used in measuring the mass balance of the Devon Island ice cap are described. The use of dyes and melt trays is recommended in the superimposed-ice and firn zones of sub-polar glaciers. The north-west part of the ice cap was studied in most detail and has had a slightly negative net balance for the period 1961-66. An inverse relationship between mean net balance(bn)and elevation of the equilibrium line in the north-west part of the ice cap indicates that the mean net balance there would be zero with an equilibrium line at 920 m (±80 m) elevation. Accumulation on the ice cap is greatest in the south-east but the measurements suggest that the mean net balance there is similar to the mean net balance on the rest of the ice cap. It is concluded that the present accumulation pattern must have existed for several hundreds, and possibly thousands of years. A study of firn stratigraphy and of variations in the elevation of the firn and equilibrium lines indicates that between 1961 and 1966 only 1962 had a more negative mean net balance than the average value for the period 1934-60. During the same 26 year period the net balance at 1 787 m elevation has varied, but summer conditions do not appear to have changed significantly.


1970 ◽  
Vol 9 (57) ◽  
pp. 325-336 ◽  
Author(s):  
R.M. Koerner

Methods used in measuring the mass balance of the Devon Island ice cap are described. The use of dyes and melt trays is recommended in the superimposed-ice and firn zones of sub-polar glaciers. The north-west part of the ice cap was studied in most detail and has had a slightly negative net balance for the period 1961-66. An inverse relationship between mean net balance (bn) and elevation of the equilibrium line in the north-west part of the ice cap indicates that the mean net balance there would be zero with an equilibrium line at 920 m (±80 m) elevation. Accumulation on the ice cap is greatest in the south-east but the measurements suggest that the mean net balance there is similar to the mean net balance on the rest of the ice cap. It is concluded that the present accumulation pattern must have existed for several hundreds, and possibly thousands of years. A study of firn stratigraphy and of variations in the elevation of the firn and equilibrium lines indicates that between 1961 and 1966 only 1962 had a more negative mean net balance than the average value for the period 1934-60. During the same 26 year period the net balance at 1 787 m elevation has varied, but summer conditions do not appear to have changed significantly.


1979 ◽  
Vol 22 (86) ◽  
pp. 25-41 ◽  
Author(s):  
R. M. Koerner

AbstractMeasurements made on traverses over ice caps in the Queen Elizabeth Islands show that there is a region of very high accumulation (>40 g cm–2 year–1) on the slopes facing Baffin Bay and one of low accumulation (<15 g cm–2 year–1) in the interior parts of northern Ellesmere Island. Ablation rates in summer show much less regional variation over the same ice caps except for lower rates along the north-west edge of the islands and possibly on the Baffin Bay slopes as well. However, there is a stronger relationship between ablation and elevation which is exponential below the firn line. From the fractional 18O content of the snow it is shown that Baffin Bay contributes significant amounts of moisture (>20% of the total) to the Baffin Bay slopes. In addition the Arctic Ocean is seen as another, but much less significant, moisture source. The δ18O data show two effects on the condensation processes—an orographic one (i.e. adiabatic cooling) and a distance-from-source effect (isobaric cooling) where the source is somewhere to the south-east of the islands.


1979 ◽  
Vol 22 (86) ◽  
pp. 25-41 ◽  
Author(s):  
R. M. Koerner

AbstractMeasurements made on traverses over ice caps in the Queen Elizabeth Islands show that there is a region of very high accumulation (&gt;40 g cm–2year–1) on the slopes facing Baffin Bay and one of low accumulation (&lt;15 g cm–2year–1) in the interior parts of northern Ellesmere Island. Ablation rates in summer show much less regional variation over the same ice caps except for lower rates along the north-west edge of the islands and possibly on the Baffin Bay slopes as well. However, there is a stronger relationship between ablation and elevation which is exponential below the firn line. From the fractional18O content of the snow it is shown that Baffin Bay contributes significant amounts of moisture (&gt;20% of the total) to the Baffin Bay slopes. In addition the Arctic Ocean is seen as another, but much less significant, moisture source. The δ18O data show two effects on the condensation processes—an orographic one (i.e. adiabatic cooling) and a distance-from-source effect (isobaric cooling) where the source is somewhere to the south-east of the islands.


1993 ◽  
Vol 130 (3) ◽  
pp. 301-318 ◽  
Author(s):  
Matthew R. Bennett ◽  
Geoffrey S. Boulton

AbstractThe aim of this paper is to demonstrate that much of the ‘hummocky moraine’ present within the northern part of the LochLomond Readvance ice cap formerly situated in the North West Scottish Highlands may be interpreted as suites of ice-front moraines deposited during active decay. These landforms can be used to reconstruct ice cap decay, whichleads to important insights into the shrinking form of the ice cap and associated environmental conditions. Evidence has been collected from 10803 airphotographs and from detailed field survey. It is presented at three spatial scales.


1980 ◽  
Vol 25 (93) ◽  
pp. 425-438
Author(s):  
B. Dey

AbstractThe study reported here illustrates the unique value of NOAA thermal infrared (TIR) images for monitoring the North Water area in Smith Sound and northern Baffin Bay during the periods of polar darkness. Wintertime satellite images reveal that, during the months of December through February, open water and thin ice occur in a few leads and polynyas. However, in March, the areas of open water and thin ice decrease to a minimum with a consequent higher concentration of ice. Two ice dams, in northern Kennedy Channel and in northern Smith Sound, regulate the flow of ice into northern Baffin Bay and also determine the areal variations of open water and thin ice in Smith Sound.


1954 ◽  
Vol 2 (16) ◽  
pp. 423-428

AbstractMorsárjökull is a small outlet glacier of Vatnajökull, Iceland. Two outlet streams from the ice cap unite at the foot of a precipitous step and carry a well-developed medial moraine; the north-west glacier stream is fed by a steep ice fall, the south-eastern one has been fed only by avalanches since 1938.The movement of the glacier was measured and showed that the alternate dark and light ogives were one year’s movement apart. Their characteristics are described and tentative suggestions concerning their mode of origin are proposed.


1975 ◽  
Vol 14 (71) ◽  
pp. 267-274 ◽  
Author(s):  
R. S. Bradley

Equilibrium-line altitudes on the White Glacier, Axel Heiberg Island, and the north-west sector of the Devon Ice Cap are shown to be closely related to mean July freezing-level heights at nearby upper-air weather stations. An inverse relationship between July freezing-level heights and mass balance on the Devon Ice Cap is also shown. Reasons for such correlations are suggested and some limitations of the relationship are outlined. Recent lowering of the freezing level in July is discussed in relation to the theoretical “steady-state” equilibrium-line altitudes in the Canadian high Arctic. It is suggested that positive mass-balance years have predominated over a large part of northern Ellesmere Island and north-central Axel Heiberg Island since 1963, and some glaciological evidence supporting this hypothesis is given.


1971 ◽  
Vol 10 (59) ◽  
pp. 245-254 ◽  
Author(s):  
R. A. Souchez

AbstractThe north-west margin of the main ice cap in south-western Ellesmere Island is fringed by ice-cored moraines. The formation of these moraines seems to be more complex than simple upwarping of the foliation bands at the margin of the ice cap. At one locality, where outer and inner zones can be distinguished on the basis of lithological composition, debris in the outer zone is composed of material from farther back under the ice cap than debris in the inner zone. In another locality, localized ridges cross each other independently of the trend of the main ridge.The time required to obtain the quantity of debris forming the moraine at the ice surface is estimated to be between 65 and 300 years.


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