Emerging investigator series: a 14-year depositional ice record of perfluoroalkyl substances in the High Arctic

2017 ◽  
Vol 19 (1) ◽  
pp. 22-30 ◽  
Author(s):  
John J. MacInnis ◽  
Katherine French ◽  
Derek C. G. Muir ◽  
Christine Spencer ◽  
Alison Criscitiello ◽  
...  

Detection of perfluoroalkyl substances from a remote ice cap indicate the importance of indirect and novel direct atmospheric sources.

ARCTIC ◽  
2016 ◽  
Vol 69 (5) ◽  
pp. 1 ◽  
Author(s):  
Bjarne Grønnow

The settlement and subsistence patterns of the Inughuit of the Avanersuaq (Thule area) are described and analyzed for the years 1910 to 1953, when Knud Rasmussen’s trading station at Dundas was active. Inughuit subsistence was based on the rich biotic resources of the North Water polynya between Ellesmere Island and Greenland, but the analysis shows that trade, primarily with fox furs at the Thule Station, also played a major role in shaping the settlement pattern of the period. During the Thule Station Period, the named winter settlements amounted to c. 40 sites; however, only 10–15 of them were settled at any given time. The Inughuit settlement close to the station, Uummannaq, soon became the largest site in the area. The sources enable us to follow changes of residence of some hunting families over four decades. By moving their winter sites every second or third year, the families gained primary knowledge of the topography and seasonal variation of the hunting grounds in the entire Thule district during their active years. In the same way, they connected with diverse family networks through the years. Tracing the sledge routes that connected the sites over great distances reveals how decisive proximity to main and escape routes over the Ice Cap was for site location. Dog sledge technology, and thus capacity to transport people, gear, and stored food, boomed during the Thule Station Period with the wealth created from trade and access to raw materials. Mapping the main hunting grounds on the sea ice and modeling the hunters’ annual range of possibilities for accessing different game—mainly walrus, ringed seal, narwhal, and sea birds (plus some caribou)—showed that ringed seal formed the bread and butter of the subsistence economy. However, bulk resources, gained in particular from intensive spring walrus hunts at a few hot spots, as well as carefully timed consumption and sharing of the stored meat and blubber, were keys to life at the North Water polynya. Temporary settlement at the trading stations in the area—a couple of winters at a time—was also part of the risk management strategy of the Inughuit.


1997 ◽  
Vol 43 (145) ◽  
pp. 489-494 ◽  
Author(s):  
Julian A. Dowdeswell ◽  
Meredith Williams

AbstractLandsat digital imagery was used to search the island archipelagos of Franz Josef Land, Severnaya Zemlya and Novaya Zemlya, Russian High Arctic, for the presence of looped moraines characteristic of past glacier surges. The imagery provides almost complete summer-time coverage of the 60 000 km2 of ice in these islands. very few surge-type glaciers are identified: none in Franz Josef Land, three in Novaya Zemlya and two on Severnaya Zemlya. This contrasts greatly with Svalbard (ice-covered area 36 600 km2), to the west, where 36% of glaciers and ice-cap drainage basins are inferred to surge. The strong climatic gradient across the Eurasian High Arctic, with decreasing temperature and moisture eastward, may provide a gross control on this pattern through colder glacier thermal structure, limiting basal drainage on the thinner ice masses in particular.


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.


1987 ◽  
Vol 33 (114) ◽  
pp. 162-168 ◽  
Author(s):  
M.C. Serreze ◽  
R.S. Bradley

AbstractHourly measurements of incoming short-wave and long-wave radiation, surface albedo, and net radiation were made on and around a plateau ice cap on north-eastern Ellesmere Island during the summers of 1982 and 1983. These data were stratified by cloud type and amount. All cloud types increased incoming long-wave radiation, especially low dense clouds, fog, and clouds associated with snowfall. Relative transmission of incoming short-wave radiation, expressed as a percentage of clear-sky radiation receipts, was high for all cloud types compared to clouds at lower latitudes. With high surface albedo (≥0.75), net radiation was strongly and positively correlated with net long-wave radiation but showed little relationship to net short-wave radiation. By contrast, with low surface albedo (≤0.20) net radiation was negatively correlated with net long-wave radiation but positively correlated with net short-wave radiation. Under high-albedo conditions, an increase in cloudiness led to higher values of net radiation but under low-albedo conditions net radiation decreased as cloud cover increased. Survival of a snow cover would seem to be favoured if the seasonal decline in albedo is accompanied by a corresponding increase in cloudiness.


1987 ◽  
Vol 33 (113) ◽  
pp. 68-71 ◽  
Author(s):  
D. J. A. Evans ◽  
T. G. Fisher

AbstractEvidence of a recent (1985) ice-cliff avalanche from an outlet lobe of a small plateau ice cap on north-west Ellesmere Island is discussed. Former avalanche events are evidenced by debris lying outside the 1985 avalanche material. Periodic activity seems to be linked to the build-up of melt water in the crevasses of the outlet lobe during the melt season. The exact magnitude and frequency of events are unknown. Some implications to geomorphology and the sedimentology of sub-polar glaciers are discussed.


2014 ◽  
Vol 9 (4) ◽  
pp. 045009 ◽  
Author(s):  
Meng Zhao ◽  
Joan Ramage ◽  
Kathryn Semmens ◽  
Friedrich Obleitner

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

AbstractEquilibrium-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.


2008 ◽  
Vol 48 ◽  
pp. 159-170 ◽  
Author(s):  
Christina Bell ◽  
Douglas Mair ◽  
David Burgess ◽  
Martin Sharp ◽  
Michael Demuth ◽  
...  

AbstractInterpretation of ice mass elevation changes observed by satellite altimetry demands quantification of the proportion of elevation change which is attributable to variations in firn densification. Detailed stratigraphic logging of snowpack structure and density was carried out at ~1km intervals along a 47 km transect on Devon Ice Cap, Canada, in spring (pre-melt) and autumn (during/ after melt) 2004 and 2006 to characterize seasonal snowpack variability across the full range of snow facies. Simultaneous meteorological measurements were gathered. Spring (pre-melt) snowpacks show low variability over large spatial scales, with low-magnitude changes in density. The end-of-summer/ autumn density profiles show high variability in both 2004 and 2006, with vastly different melt regimes generating dissimilar patterns of ice-layer formation over the two melt seasons. Dye-tracing experiments from spring to autumn 2006 reveal that vertical and horizontal distribution of meltwater flow within and below the annual snowpack is strongly affected by the pre-existing, often subtle stratigraphic interfaces in the snowpack, rather than its bulk properties. Strong interannual variability suggests that using a simple relationship between air temperature, elevation and snowpack densification to derive mass change from measurements of elevation change across High Arctic ice caps may be misguided. Melt timing and duration are important extrinsic factors governing snowpack densification and ice-layer formation in summer, rather than averaged air temperatures.


2019 ◽  
Vol 53 (18) ◽  
pp. 10753-10762 ◽  
Author(s):  
John J. MacInnis ◽  
Igor Lehnherr ◽  
Derek C. G. Muir ◽  
Kyra A. St. Pierre ◽  
Vincent L. St. Louis ◽  
...  

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