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- Cosgrove, Christopher, et al.
(författare)
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Environmental controls on snow water equivalent in two sub-Arctic mountain catchments
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Spatial variability of seasonal snow depth poses a challenge when estimating snow water equivalent (SWE) from in-situ measurements in mountainous areas. Poor accessibility, complex topographic effects and localized microclimates make extrapolation of in-situ SWE measurements to a basin scale difficult. Remotely-sensed passive microwave SWE products are also inaccurate in complex terrain and/or at the forest-alpine tundra transition zone. To address these caveats, we investigated the relative importance of landscape qualities (altitude, slope, aspect, vegetation) and climate (winter temperatures, precipitation) on SWE distribution in two sub-Arctic mountainous catchments in Hemavan, Sweden, and Wolf Creek, Yukon, Canada. The two catchments are comparable, but have contrasted climate regimes. In-situ SWE measurements were made in March-April 2014 across the forest-tundra ecotone in both catchments. These were supplemented with historical snow-survey data since 2012 in Hemavan, and 1993 in Wolf Creek. Pairwise linear regressions of SWE against different landscape factors indicate that overall, altitude exerts the largest control on SWE at both Hemavan and Wolf Creek, but its effect is lesser within individual vegetation zones. In other respects, the two sites differ. SWE is inversely correlated to surface slope at forested sites in Hemavan (R^2 = 0.57, p = 0.25), but not in Wolf Creek. Slope aspect is positively correlated with SWE at forest-tundra transition sites (R^2 = 0.49, p = 0.12) in Wolf Creek, but not in Hemavan. For alpine tundra sites, slope angle strongly influences SWE in Hemavan (R^2 = 0.58, p = 0.24), but only weakly in Wolf Creek (R^2 = 0.05, p = 0.71). We discuss possible causes of these inter-catchment differences, and also evaluate the effect of inter-annual climate variations on SWE distribution at Wolf Creek using the long-term snow-survey record. Finally, we compare and discuss SWE estimates obtained by three different field measurement methods.
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| 2. |
- Schaffer, Nicole, et al.
(författare)
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Volume and mass changes over Penny Ice Cap, Baf-fin Island, from 2005-2013 determined from repeat air-borne laser altimetry.
- 2014
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Ingår i: Proceedings of the 2014 IASC Workshop on the dynamics and mass budget of Arctic glaciers.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Recent observations of accelerated glacier wastage in Greenland and Alaska haveprompted reassessments of mass balance trends and volume changes on Cana-dian Arctic glaciers and ice caps. While long surface mass balance measurementsare available from glaciers and ice caps in the Queen Elizabeth Islands (e.g., WhiteGlacier, Devon Ice Cap, Meighen Ice Cap), no such records exist for Baffin Islandglaciers. In the absence of such data, air- and space-borne measurements canbe used in combination with in situ data to evaluate historical and recent trendsin ice cover changes. Here, we use repeat laser airborne altimetry surveys con-ducted in 2005 and 2013 by NASA to estimate recent volume and mass changesof Penny Ice Cap, the southernmost large ice cap on Baffin Island ( 66N). Thesedata are validated against in-situ surface mass balance measurements from 2013and IceSat derived elevation change from 2003-2009. Once validated, surface el-evation changes along altimetry lines are extrapolated to the entire ice cap usinga digital elevation model (DEM). Changes in areal extent of the ice cap are con-strained using satellite imagery (e.g. Landsat). From these data we estimate thetotal mass wastage of the ice cap and its recent contribution to sea level rise. Thiswork builds on previous surveys for the period 1995-2005 (Abdalati et al.,2004;Gardneret al.,2012).
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| 3. |
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| 4. |
- Zdanowicz, Christian, 1966-, et al.
(författare)
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Ice cores from the St-Elias Mountains, Yukon Territory, Canada : Their significance for the Holocene climate history, volcanism and air pollution trends in the Northwest Pacific region
- 2014
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Ingår i: Arctic. - : The Arctic Institute of North America. - 0004-0843 .- 1923-1245. ; 67:S1, s. 35-57
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Tidskriftsartikel (refereegranskat)abstract
- A major achievement in research supported by the Kluane Lake Research Station was the recovery, in 2001–02, of a suite of cores from the icefields of the central St. Elias Mountains, Yukon, by teams of researchers from Canada, the United States, and Japan. This project led to the development of parallel, long (10^3 – 10^4 year) ice-core records of climate and atmospheric change over an altitudinal range of more than 2 km, from the Eclipse Icefield (3017 m) to the ice-covered plateau of Mt. Logan (5340 m). These efforts built on earlier work recovering single ice cores in this region. Comparison of these records has allowed for variations in climate and atmospheric composition to be linked with changes in the vertical structure and dynamics of the North Pacific atmosphere, providing a unique perspective on these changes over the Holocene. Owing to their privileged location, cores from the St. Elias Icefields also contain a remarkably detailed record of aerosols from various sources around or across the North Pacific. In this paper we review major scientific findings from the study of St. Elias Mountain ice cores, focusing on five main themes: (1) The record of stable water isotopes (δ18O, δD), which has unique characteristics that differ from those of Greenland, other Arctic ice cores, and even among sites in the St. Elias; (2) the snow accumulation history; (3) the record of pollen, biomass burning aerosol, and desert dust deposition; (4) the record of long-range air pollutant deposition (sulphate and lead); and (5) the record of paleo-volcanism. Our discussion draws on studies published since 2000, but based on older ice cores from the St. Elias Mountains obtained in 1980 and 1996.
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