Ice thickness measurements and their implications with respect to past and present ice volumes in the Canadian High Arctic ice caps

1977 ◽  
Vol 14 (12) ◽  
pp. 2697-2705 ◽  
Author(s):  
R. M. Koerner
Keyword(s):  
High Arctic ◽  
Snow Accumulation ◽  
The Arctic ◽  
Pronounced Difference ◽  
Baffin Bay ◽  
Ice Caps ◽  
Devon Island ◽  
East And West ◽  
Axel Heiberg Island ◽  
Arctic Ice

The main ice caps on Devon Island, central and northeast Ellesmere Island, and Axel Heiberg Island were sounded using a 620 MHz radar. Ice depths were found to be generally between 300 and 800 m. The bedrock topography is everywhere very irregular. There is a pronounced difference between the thickness, and hence volume, of ice on the east and west sides of the Central Ellesmere and Devon ice caps. The greater thickness on the east sides is attributed to much higher snow accumulation rates there and it is calculated that the asymmetry between the east and west sides began to develop some 8000 years ago. The greater thickness of ice on the ice caps facing Baffin Bay must be considered in any derivation of the dimensions of the Wisconsin ice sheet from maps of isostatic rebound in the Queen Elizabeth Islands. Some of the northwest–southeast tilt of strandlines on Devon and Southern Ellesmere islands can be attributed to the suppression of rebound by these thick ice masses. It is inferred, from the greater symmetry of ice caps in Northern Ellesmere and to a lesser extent Axel Heiberg Island, that the Arctic Ocean is a much less effective moisture source than Baffin Bay.

scholarly journals Continuous Non-Marine Inputs of Per- and Polyfluoroalkyl Substances to the High Arctic: A Multi-Decadal Temporal Record

2017 ◽  
Author(s):  
Heidi M. Pickard ◽  
Alison S. Criscitiello ◽  
Christine Spencer ◽  
Martin J. Sharp ◽  
Derek C. G. Muir ◽  
...  
Keyword(s):  
Solid Phase ◽  
Ice Core ◽  
High Arctic ◽  
The Arctic ◽  
Ice Caps ◽  
Ice Cap ◽  
Devon Ice Cap ◽  
Pollutant Sources ◽  
Arctic Ice ◽  
Changes Over Time

Abstract. Perfluoroalkyl acids (PFAAs) are persistent, bioaccumulative compounds found ubiquitously within the environment. They can be formed from the atmospheric oxidation of volatile precursor compounds and undergo long-range transport through the atmosphere and ocean to remote locations. Ice caps preserve a temporal record of PFAA deposition making them useful in studying the atmospheric trends in LRT of PFAAs as well as understanding major pollutant sources and production changes over time. A 15 m ice core representing 38 years of deposition (1977–2015) was collected from the Devon Ice Cap in Nunavut, providing us with the first multi-decadal temporal ice record in PFAA deposition to the Arctic. Ice core samples were concentrated using solid phase extraction and analyzed by liquid and ion chromatography methods. Both perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) were detected in the samples, with fluxes ranging from

scholarly journals CryoSat-2 delivers monthly and inter-annual surface elevation change for Arctic ice caps

2015 ◽  
Vol 9 (3) ◽  
pp. 2821-2865 ◽  
Author(s):  
L. Gray ◽  
D. Burgess ◽  
L. Copland ◽  
M. N. Demuth ◽  
T. Dunse ◽  
...  
Keyword(s):  
Snow Accumulation ◽  
Surface Elevation ◽  
Radar Altimeter ◽  
Elevation Change ◽  
Ice Caps ◽  
Ice Cap ◽  
Winter Snow ◽  
Surface Elevation Change ◽  
Devon Ice Cap ◽  
Arctic Ice

Abstract. We show that the CryoSat-2 radar altimeter can provide useful estimates of surface elevation change on a variety of Arctic ice caps, on both monthly and yearly time scales. Changing conditions, however, can lead to a varying bias between the elevation estimated from the radar altimeter and the physical surface due to changes in the contribution of subsurface to surface backscatter. Under melting conditions the radar returns are predominantly from the surface so that if surface melt is extensive across the ice cap estimates of summer elevation loss can be made with the frequent coverage provided by CryoSat-2. For example, the average summer elevation decreases on the Barnes Ice Cap, Baffin Island, Canada were 2.05 ± 0.36 m (2011), 2.55 ± 0.32 m (2012), 1.38 ± 0.40 m (2013) and 1.44 ± 0.37 m (2014), losses which were not balanced by the winter snow accumulation. As winter-to-winter conditions were similar, the net elevation losses were 1.0 ± 0.2 m (winter 2010/2011 to winter 2011/2012), 1.39 ± 0.2 m (2011/2012 to 2012/2013) and 0.36 ± 0.2 m (2012/2013 to 2013/2014); for a total surface elevation loss of 2.75 ± 0.2 m over this 3 year period. In contrast, the uncertainty in height change results from Devon Ice Cap, Canada, and Austfonna, Svalbard, can be up to twice as large because of the presence of firn and the possibility of a varying bias between the true surface and the detected elevation due to changing year-to-year conditions. Nevertheless, the surface elevation change estimates from CryoSat for both ice caps are consistent with field and meteorological measurements. For example, the average 3 year elevation difference for footprints within 100 m of a repeated surface GPS track on Austfonna differed from the GPS change by 0.18 m.

scholarly journals Dynamics of Ice-Island Motion Near the Coast of Axel Heiberg Island, Canadian High Arctic

1989 ◽  
Vol 12 ◽  
pp. 152-156 ◽  
Author(s):  
W.M. Sackinger ◽  
M.O. Jeffries ◽  
H. Tippens ◽  
F. Li ◽  
M. Lu
Keyword(s):  
Surface Wind ◽  
High Arctic ◽  
The Arctic ◽  
Movement Direction ◽  
Canadian High Arctic ◽  
North West ◽  
The North ◽  
Pack Ice ◽  
Axel Heiberg Island ◽  
Ice Force

The largest ice island presently known to exist in the Arctic Ocean has a mass of about 700 × 106 tonnes, an area of about 26 km2, and a mean thickness of 42.5 m. Known as Hobson’s Ice Island, this large ice feature has been tracked almost continuously since August 1983 with a succession of Argos buoys. In this paper, two particular ice-island movement episodes near the north-west coast of Axel Heiberg Island are described: 6–16 May 1986 and 14–21 June 1986. Each movement episode is analyzed in terms of the forces acting on the ice island, including wind shear, water drag, water shear, Coriolis force, sea-surface tilt, and pack-ice force. Ice-island movement is generally preceded by an offshore surface wind, and a threshold wind speed of 6 m s°1 appears to be necessary to initiate ice-island motion. An angle of 50° between surface wind and ice-island movement direction is noted during one episode. The pack-ice force, which appears to be the dominant arresting factor of ice-island motion for these two episodes, varies from 100° to 180° to the left of the ice-island velocity direction, depending upon whether the ice island is accelerating or decelerating.

The Arctic Committee of 1851: A Background Study Part 1

Polar Record ◽  
1980 ◽  
Vol 20 (124) ◽  
pp. 3-17 ◽  
Author(s):  
Clive Holland
Keyword(s):  
The Arctic ◽  
Surrounding Area ◽  
Baffin Bay ◽  
North West ◽  
Devon Island ◽  
Close Proximity ◽  
Common Purpose ◽  
Ice Conditions ◽  
The Common ◽  
Private Venture

In 1850, five expeditions sailed for Baffin Bay with the common purpose of searching the Canadian Arctic for Sir John Franklin's missing North-west Passage expedition. They were all headed for different destinations and should have found themselves wintering many hundreds of miles apart; but, as chance would have it, three of them, led by Captain Horatio T. Austin, RN, Admiral Sir John Ross and the whaling master William Penny, were thrown together by ice conditions and by events. They wintered in close proximity to one another and were obliged to divide among themselves the search of the surrounding area. Ross's little private venture was too poorly equipped to contribute much, but the other two achieved very promising results: Austin's men discovered the first traces of the Franklin expedition on Devon Island and, in cooperation with Penny, located Franklin's first winter quarters on Beechey Island. In the following spring, sledge parties went out to explore hundreds of miles of new coastline; Austin found no further trace of Franklin, but Penny found persuasive evidence to suggest that the missing expedition had sailed up Wellington Channel (as, indeed, it had done, though it had not remained in that area). With the work of the travelling parties concluded, and after some conversation between Austin and Penny on 11 August 1851, all three expeditions set course for home.

Artificial radioactivity layers in the Devon Island ice cap, Northwest Territories

1976 ◽  
Vol 13 (9) ◽  
pp. 1251-1255 ◽  
Author(s):  
R. M. Koerner ◽  
H. Taniguchi
Keyword(s):  
Northwest Territories ◽  
Snow Accumulation ◽  
Polar Ice ◽  
Artificial Radioactivity ◽  
Ice Caps ◽  
Devon Island ◽  
Ice Cap ◽  
Positive Balance ◽  
Melt Water

Bomb-produced radioactive fall-out layers are evident in the firn at the top of the Devon Island ice cap and also lower down in a zone where accumulation is in the form of re-frozen melt-water. This allows 1963–1974 snow accumulation (positive balance) gradients for the same period to be determined on sub-polar ice caps in Canada.

scholarly journals Long-term effects of snowmelt timing and climate warming on phenology, growth and reproductive effort of arctic tundra plant species

2021 ◽  
Author(s):  
Esther R. Frei ◽  
Greg H.R. Henry
Keyword(s):  
Plant Species ◽  
Reproductive Effort ◽  
High Arctic ◽  
Snow Accumulation ◽  
The Arctic ◽  
Plant Responses ◽  
Long Term Effects ◽  
Passive Warming ◽  
Species Specific

Arctic regions are particularly affected by rapidly rising temperatures and altered snow regimes. Snowmelt timing depends on spring temperatures and winter snow accumulation. Scenarios for the Arctic include both decreases and increases in snow accumulation. Predictions of future snowmelt timing are thus difficult and experimental evidence for ecological consequences is scarce. In 1995, a long-term factorial experiment was set up in a High Arctic evergreen shrub heath community on Ellesmere Island, Canada. We investigated how snow removal, snow addition and passive warming affected phenology, growth and reproductive effort of the four common tundra plant species <i>Cassiope tetragona</i>, <i>Dryas integrifolia</i>, <i>Luzula arctica</i> and <i>Papaver radicatum</i>. Timing of flowering and seed maturation as well as flower production were more strongly influenced by the combined effects of snowmelt timing and warming in the two shrub species than in the two herbaceous species. Warming effects persisted over the course of the growing season and resulted in increased shrub growth. Moreover, the long-term trend of increasing growth in two species suggests that ambient warming promotes tundra plant growth. Our results confirm the importance of complex interactions between temperature and snowmelt timing in driving species-specific plant responses to climate change in the Arctic.

A 750-yr record of autumn snowfall and temperature variability and winter storminess recorded in the varved sediments of Bear Lake, Devon Island, Arctic Canada

2004 ◽  
Vol 61 (2) ◽  
pp. 134-147 ◽  
Author(s):  
Scott F. Lamoureux ◽  
Robert Gilbert
Keyword(s):  
Distal Part ◽  
Close Association ◽  
High Arctic ◽  
Lake Ice ◽  
Climate Signal ◽  
Baffin Bay ◽  
Devon Island ◽  
The Past ◽  
Bear Lake ◽  
Lake Record

The varve record from High Arctic, proglacial Bear Lake reveals a regionally coherent hydroclimatic signal as well as complexities due to changing hydroclimatic and limnologic conditions. Varve formation is strongly dependent on underflows that exhibit variability in strength during the past 750 yr. Periods with reduced underflow sedimentation and accumulation rates fail to produce varves in the distal part of the lake. Isolated coarse silt and sand grains occur in 80% of the varves and are interpreted to be niveo-aeolian in origin. Coarse (>500 μm) sand grains deposited on the lake ice by strong winter winds are notably less common since A.D. 1850, likely due to reduced storminess. Regression of the varve thickness record with meteorological records indicates high correlations with autumn (September and October) temperatures and total monthly snowfall. These correlations are best at times when underflow activity is sufficiently strong to produce varves throughout the lake. The close association with warmer temperatures and snow-bearing synoptic systems moving north in Baffin Bay suggests that the primary climate signal in the varves is varying autumn snow pack that controls nival discharge in the following year. The similarity between the other records of melt season temperature and sea-ice cover and the Bear Lake record suggests that summer and autumn conditions were generally similar across the Baffin Bay region through much of the last millennium.

scholarly journals Global Warming and Climate Change: Science and Politics

2013 ◽  
Vol 32 (1) ◽  
pp. 61-66 ◽  
Author(s):  
Cliff Ollier
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Sea Level ◽  
Ice Cores ◽  
Snow Accumulation ◽  
The Arctic ◽  
Solar Cycles ◽  
Ice Caps ◽  
Science And Politics ◽  
Dangerous Climate Change

Abstract The threat of dangerous climate change from anthropogenic global warming has decreased. Global temperature rose from 1975 to 1998, but since then has levelled off. Sea level is now rising at about 1.5mm per year based on tide gauges, and satellite data suggests it may even be falling. Coral islands once allegedly threatened by drowning have actually increased in area. Ice caps cannot possibly slide into the sea (the alarmist model) because they occupy kilometres-deep basins extending below sea level. Deep ice cores show a succession of annual layers of snow accumulation back to 760,000 years and in all that time never melted, despite times when the temperature was higher than it is today. Sea ice shows no change in 30 years in the Arctic. Emphasis on the greenhouse effect stresses radiation and usually leads to neglect of important factors like convection. Water is the main greenhouse gas. The CO2 in the ocean and the atmosphere are in equilibrium: if we could remove CO2 from the atmosphere the ocean would give out more to restore the balance. Increasing CO2 might make the ocean less alkaline but never acid. The sun is now seen as the major control of climate, but not through greenhouse gases. There is a very good correlation of sunspots and climate. Solar cycles provide a basis for prediction. Solar Cycle 24 has started and we can expect serious cooling. Many think that political decisions about climate are based on scientific predictions but what politicians get are projections based on computer models. The UN’s main adviser, the IPCC, uses adjusted data for the input, their models and codes remain secret, and they do not accept responsibility for their projections.

scholarly journals Glaciers and ice caps through the Holocene: A pan–Arctic synthesis of lake–based reconstructions

2021 ◽  
Author(s):  
Laura J. Larocca ◽  
Yarrow Axford
Keyword(s):  
Greenland Ice Sheet ◽  
High Arctic ◽  
Early Holocene ◽  
The Arctic ◽  
Boreal Summer ◽  
Russian Arctic ◽  
The Holocene ◽  
Ice Caps ◽  
Summer Insolation ◽  
Arctic Regions

Abstract. The recent retreat of nearly all glaciers and ice caps (GICs) located in Arctic regions is one of the most clear and visible signs of ongoing climate change. This paper synthesizes published records of Holocene GIC fluctuations from lake archives, placing their recent retreat into a longer–term context. Our compilation includes sixty–six lake–based GIC records (plus one non–lake–based record from the Russian Arctic) from seven Arctic regions: Alaska; the archipelagos of the eastern Canadian Arctic; GICs peripheral to the Greenland Ice Sheet; Iceland; the Scandinavian peninsula; Svalbard; and the Russian high Arctic. For each region, and for the full Arctic, we summarize evidence for when GICs were smaller than today or absent altogether, indicating warmer than present summers, and evidence for when GICs regrew in lake catchments, indicating summer cooling. Consistent with orbitally driven high boreal summer insolation in the early Holocene, the pan–Arctic compilation suggests that the majority (50 % or more) of studied GICs were smaller than present or absent by ~10 ka. The regional compilations suggest even earlier GIC loss, and thus warmth, in the Russian Arctic and in Svalbard. We find the highest percentage (>90 %) of Arctic GICs smaller than present or absent in the middle Holocene ~7–6 ka, probably reflecting more spatially ubiquitous and consistent summer warmth during this period than in the early Holocene. Following this interval of widespread warmth, our compilation shows that GICs across the Arctic began to regrow, and summers began to cool by ~6 ka. Together, the pan–Arctic records also suggest two periods of enhanced GIC growth in the mid–to–late Holocene, from ~4.5–3 ka and after ~2 ka. The regional records show substantial variability in the timing of GIC regrowth within and between regions, suggesting that the Arctic did not cool synchronously despite the smooth and hemispherically symmetric decline in Northern Hemisphere summer insolation. In agreement with other studies, this implies a combined response to glacier–specific characteristics such as topography, and to other climatic forcings and feedback mechanisms, perhaps driving periods of increased regional cooling. Today, the direction of orbital forcing continues to favor GIC expansion, however, the rapid retreat of nearly all Arctic GICs underscores the current dominance of anthropogenic forcing on GIC mass balance. Our review finds that in the first half of the Holocene, most of the Arctic’s small GICs became significantly reduced or melted away completely in response to summer temperatures that, on average, were only moderately warmer than today. In comparison, future projections of temperature change in the Arctic far exceed estimated early Holocene values in most locations, portending the eventual loss of most of the Arctic’s small GICs.

The Mass Balance of Circum-Arctic Glaciers and Recent Climate Change

1997 ◽  
Vol 48 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Julian A. Dowdeswell ◽  
Jon Ove Hagen ◽  
Helgi Björnsson ◽  
Andrey F. Glazovsky ◽  
William D. Harrison ◽  
...  
Keyword(s):  
Mass Balance ◽  
Ice Age ◽  
The Arctic ◽  
Surface Mass Balance ◽  
Mass Balances ◽  
Negative Mass ◽  
Surface Mass ◽  
Ice Caps ◽  
Recent Climate ◽  
Arctic Ice

The sum of winter accumulation and summer losses of mass from glaciers and ice sheets (net surface mass balance) varies with changing climate. In the Arctic, glaciers and ice caps, excluding the Greenland Ice Sheet, cover about 275,000 km2of both the widely glacierized archipelagos of the Canadian, Norwegian, and Russian High Arctic and the area north of about 60°N in Alaska, Iceland, and Scandinavia. Since the 1940s, surface mass balance time-series of varying length have been acquired from more than 40 Arctic ice caps and glaciers. Most Arctic glaciers have experienced predominantly negative net surface mass balance over the past few decades. There is no uniform recent trend in mass balance for the entire Arctic, although some regional trends occur. Examples are the increasingly negative mass balances for northern Alaska, due to higher summer temperatures, and increasingly positive mass balances for maritime Scandinavia and Iceland, due to increased winter precipitation. The negative mass balance of most Arctic glaciers may be a response to a step-like warming in the early twentieth century at the termination of the cold Little Ice Age. Arctic ice masses outside Greenland are at present contributing about 0.13 mm yr−1to global sea-level rise.

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