Glaciers and Climate Change Flashcards

1
Q

At the largest spatial and temporal scales, an increase in temperature leads to…

At smaller scales…

A

Sea level rise

Its not that simple

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2
Q

What’s the link between glaciers and climate?

A

Glacier mass balance

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3
Q

What are the factors driving glacier responses to climate change?

A
Glacier temperature 
Subglacial hydrology 
Nature of the bed
Surges
Aquatic margin
Size, shape, aspect
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4
Q

What is glacier temperature dependent on?

A

Metamorphism- how easily it turns from snow to ice

Response to mass balance changes
- longest for long or slowly flowing glaciers

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5
Q

What is hypsometry?

A

Distribution of glacier area over its altitudinal range

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6
Q

What is AAR?

A

Accumulation area ratio- ratio between accumulation area and area of entire glacier.

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7
Q

What does Hughes (1986) suggest happens when ice streams enter the water at the aquatic margin?

A

There is enhanced fast flow.

Fast flow leads to increased crevassing.

Enhanced calving and allow penetration of meltwater into bed.

Increased flow.

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8
Q

Reasons for dramatic melting

A

It has been argued that enhanced basal lubrication.
- Increased melting = more water down to the bed = increased lubricated = glacier shoot forward = lower altitudes = more melting

Hydro-fracturing of water filled crevasses- accompanied by a release of back stresses
- Water can come from the bottom up where the glacier is floating cracking them open wider, flowing faster

Early development of the summer channelised system (bed already lubricated)
- the hydrological system adapts to extra water so it can’t go any faster remaining stable

Calving
- Once the glacier meets a water body, the heat from the water will cause calving

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9
Q

Internal effects/ surges are…

A

Irrespective of global warming

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10
Q

Rigid bed model (Kamb et al., 1985)

High water pressure ->

A

Increased sliding
Increased cavitation
Changes system from a tunnel to linked cavity system

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11
Q

Deforming bed model (Clark et al., 1984)

High water pressure ->

A

Surge triggered by destruction of the drainage system due to deformation of the till

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12
Q

Thermal/ deformation (Murray et al., 2003)

Cold toe - ice builds up until pmp reached

A
Increased meltwater 
Basal sliding 
More heat
More melting 
Until ice thins and refreezing
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13
Q

Storage (Lingle and Fatland, 2003)

Water added to englacial storage

A

In winter this drains- too much for the constricted winter system, and basal sliding or till failure

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14
Q

Mass and energy flux (Sevestre and Benn, 2015)

Glacier must be in balance (heat convection or drainage system)

A

Typical ‘in balance’ glaciers

  • temperate wet
  • small cold dry

Typical ‘out of balance’

  • large cold dry
  • polythermal
  • temperature dry
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15
Q

From here just read off slides- Non climatic? What has recent warming meant?

A

Glaciers can’t surge

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