Irvine-Fynn et al 2011 (1 & 2) Flashcards
The manner by which meltwater drains through a glacier is critical to…
Ice dynamics, runoff characteristics, and water quality.
Polar ice masses, rather than being impermeable, are interlaced with drainage systems, comprising what components?
Surface (supraglacial), internal (englacial), and basal (subglacial) hydraulic components.
Arctic valley glaciers has illustrated that glacier hydrology and ice motion are intricately linked as a result of…
the role of meltwater accessing the glacier sole and reducing basal traction.
Glacier hydrology and ice motion being linked drives..
The coupling between polar glacier hydrology and dynamics has the potential to
glacier surge cycles in higher latitudes and more recently has been invoked to explain dynamics at ice sheet margins.
to accelerate ice losses via a positive feedback whereby the rate of mass transfer to lower elevations is increased.
A glacier’s hydrological architecture affects…
the timing and volume of meltwater release and the quality of waters delivered to downstream terrestrial and/or aquatic environments.
The hydrological configuration of a glacier is significantly influenced by its…
Thermal structure.
The thermal structure of a glacier is ultimately dependent on…
its heat balance, which is controlled by intrinsic and extrinsic factors affecting processes of conduction, advection, and latent heat transfer [Paterson, 1994].
Polythermal glaciers are defined as
ice masses displaying a perennial concurrence of temperate and cold ice
Temperate ice is at the
Cold ice is
pressure melting point (PMP) exhibiting coexisting water and ice and an interstitial liquid content up to ∼9% by volume.
below PMP and exhibits negligible interstitial water.
Where cold ice characterizes the glacier bed interface…
the high adhesive strength of cold ice ensures the glacier is effectively frozen to the rock substrate.
Polythermal glacier regimes are a common, characteristic response in regions with…
protracted subfreezing winter air temperatures where steep, annual near‐surface temperature gradients result in the net conduction of heat away from the glacier ice and a deeper penetration of the winter cold wave.
A temperate ice zone may be sustained where…
Ice thickness is in excess of the cold wave penetration depth or where ice overburden pressure elevates ice temperature to the PMP.
The process of temperate ice advection is further complicated by the nature of…
See this paper for diagrams later
the accumulation regime and leads to a characteristic contrast between the nontemperate glaciers of the continental Canadian Arctic and those located in maritime Svalbard and Scandinavia: Differences in typical winter temperatures and snow depths result in regional disparity in insulation and latent heat release during snow metamorphosis and burial.
Glacier thinning as a response to rising air temperatures may result in…
either a reduction or an increase in the spatial extent of cold ice.
Truly temperate glaciers, by definition, may have a limited occurrence, perhaps restricted to…
areas of >2 m of winter snowfall where both restricted penetration and seasonal elimination of the cold wave can occur.
Because of their extensive cold ice content, for similar geometry, many nontemperate or polythermal glaciers exhibit…
reduced rates of ice deformation and fracturing over considerable areas, resulting in a low crevasse density compared to their temperate counterparts.
At the start of the Arctic melt season, a proportion of meltwater freezing within and at the base of the snowpack and/or percolation zone forms At the start of the Arctic melt season, a proportion of meltwater freezing within and at the base of the snowpack and/or percolation zone forms…
Superimposed ice, this can be a significant contribution to accumulation upon many High Arctic glaciers
Superimposed ice accentuates…
the reduced permeability of nontemperate glaciers so that accumulation of meltwater on the glacier surface is pronounced during the early period of the ablation season.
After the removal of snow cover, the surface and ice dynamic conditions upon nontemperate glaciers in the Arctic can also facilitate the development of…
Weathering crust to depths of the order of several meters in the ablation areas.
Observations of degrading surface ice layer at nontemperate glaciers with a density decreasing to ∼0.5 g cm−3 at relatively shallow (<0.5 m) depths show that the seasonal weathering crust can be enhanced by the presence of….
The development of the weathering crust in cold regions can also be promoted by shallow (<3 m) fracturing caused by…
Cryoconite, the biologically active dust common to glacier surfaces that can enhance localized melting.
Large stresses from thermal expansion
Where lakes are absent, slush flows (mobilized saturated snow or firn)…
drain into topographic lows and can initiate or reopen antecedent supraglacial channel routes.
The persistence of snow bridges and metamorphosed and deforming ice over these incised flow paths results…
enclosed, high‐roofed englacial channels). Meltwater refreezing on the incised channel walls near the ice surface may also aid in the isolation of a supraglacial stream within the englacial environment, as can early season slush flows associated with supraglacial snowmelt floods
