| 项目编号: | NE/K004956/2
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| 项目名称: | Airborne geophysical investigations of conditions at the bed of fast-flowing outlet glaciers of large Canadian Arctic ice caps |
| 作者: | Martin John Siegert
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| 承担单位: | Imperial College London
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| 批准年: | 2013
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| 开始日期: | 2014-01-05
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| 结束日期: | 2016-31-03
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| 资助金额: | GBP13501
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| 资助来源: | UK-NERC
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| 项目类别: | Research Grant
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| 国家: | UK
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| 语种: | 英语
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| 特色学科分类: | Climate & Climate Change 
; (25%)
; Geosciences 
; (75%)
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| 英文摘要: | Recent work has shown that the single largest unknown in assessing the contribution of mountain glaciers and ice caps to
contemporary global sea-level rise is the rate of mass loss by iceberg calving from large Arctic ice caps (Radic and Hock,
2011, Nature Geoscience). The largest ice caps in the Arctic, and indeed the largest ice masses outside the Antarctic and
Greenland ice sheets, are those of the Canadian Arctic islands. Importantly, new findings indicate that, for 2004-2009, a
sharp increase in the rate of mass loss also makes the Canadian Arctic Archipelago the single largest contributor to global
sea-level rise outside Greenland and Antarctica (Gardner et al., 2011, Nature). Each of these large Canadian ice caps is
divided into a series of drainage basins that flow into fjords via narrow, heavily crevassed fast-flowing outlet glaciers which
dissect the islands' fringing mountains. A major question for scientists and policymakers is, therefore, how these ice caps
will continue to react to the temperature rises that are predicted for the 21st century, noting that Atmospheric General
Circulation Models predict that temperature rise will be significantly greater in the Arctic than at lower latitudes. Numerical
modelling of large ice masses is constrained, however, by a lack of knowledge of the geometry and nature of the bed of
these outlet glaciers. We will acquire geophysical data from ice-cap outlet glaciers draining the large ice caps on Ellesmere
and Devon islands in the Canadian Arctic using an airborne ice-penetrating radar, laser altimeter, gravimeter,
magnetometer and GPS instruments. We will focus on three key areas of each drainage basin: the heavily crevassed fastflowing
outlet glaciers themselves, an upper transition zone between the ice-cap interior and the narrow outlet glaciers; and
the grounding zone marking the transition to floating ice tongues at the head of some Canadian High-Arctic fjords. Our
scientific objectives are: (a) to determine ice-surface and subglacial-bed elevation; (b) to characterize the substrate, in
particular whether it is bedrock or deformable sediment; (c) to establish the distribution of subglacial melting; (d) to reveal
basal character changes at the transition zones between inland ice, outlet glaciers and the grounding zone; (e) to provide
new estimates of outlet glacier calving fluxes and their variability on up to decadal timescales. This information, integrated
with satellite datasets on outlet-glacier surface motion and our earlier observations of the regional-scale geometry of these
ice caps, will provide fundamental boundary conditions for the numerical modelling of these ice caps and, thus, how they
may respond to atmospheric and ocean warming over the coming decades, with implications for sea-level rise. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/102035
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| Appears in Collections: | 科学计划与规划
气候变化与战略
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作者单位: | Imperial College London
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| Recommended Citation: | |
Martin John Siegert. Airborne geophysical investigations of conditions at the bed of fast-flowing outlet glaciers of large Canadian Arctic ice caps. 2013-01-01.
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