Glaciers as natural systems:

Question 1

What is a glacial system?

Answer 1

Glacier can be viewed as an open system with inputs and outputs from external systems, such as atmospheric and fluvial systems.

Question 2

Inputs:

Answer 2

• Main input is snow, also avalanches.
• Snow over many years becomes increasingly compacted into high density clear glacial ice.

Question 3

Outputs:

Answer 3

• Main output is meltwater.
• Calving may occur when the ice front extends out over the water.
• Evaporation and sublimation are also outputs.

Question 4

Energy:

Answer 4

Glacier’s mass combines with gravity to generate potential energy.

As glacier’s move this energy is converted into kinetic energy which enables the glacier to carry out processes like erosion, transportation and deposition.

Question 5

Stores/Components:

Answer 5

• Main stores are snow and ice
• May be seasonal variations in these stores.
• Over last 30 yrs stores have shown a decline due to global warming.

Question 6

Flows/Transfers:

Answer 6

Many flows and transfers such as: evaporation, sublimation, meltwater flow, basal sliding and internal deformation.

• Flows and transfers are more active in warmer environments where there are significant seasonal variations in temperature.

Question 7

Positive/Negative feedback loops:

Answer 7

• A feedback loop is a type of chain reaction.
• Positive feedback loop = amplify the change in the inputs or outputs. Moving the system even further away from it’s original state. e.g global warming

Negative feedback loop = counteract the change in the inputs or outputs. System responds by decreasing the effects of the change. Closer to it’s original state. e.g increased planting of trees.

Question 8

Dynamic equilibrium:

Answer 8

Where landforms and processes are in a state of balance. When accumulation and ablation are equal, the equilibrium line will stay in the same place. However, as this balance shifts the line will move up and down the glacier.