Glaciers as Natural Systems Flashcards
What are the inputs of a glacier?
- Mass
- Energy
What are the mass inputs of a glacier?
- Direct snowfall
- Blown snow
- Avalanches / rockfalls
What are the energy inputs of a glacier?
- Solar radiation
- Geothermal energy
What are the outputs of a glacier?
- Icebergs (calving)
- Meltwater
- Water vapour
Which two processes lead to water vapour as a glacial output?
- Evaporation
- Sublimation
Why do warm-based glaciers move more rapidly than cold-based glaciers?
The presence of subglacial meltwater allows basal sliding to occur.
Which two forms of energy contribute to glacial movement?
- Kinetic energy
- Gravitational potential energy
What are the three types of glacial stores?
- Subglacial
- Englacial
- Supraglacial
What are the two types of flows through which glaciers move?
- Extensional flow
- Compressional flow
What is a positive feedback mechanism?
A chain of events/processes which amplifies the effect of the original change.
What is a negative feedback mechanism?
A chain of events/processes which nullifies the effect of the original change.
What is an example of positive feedback?
- Temperatures increase
- Ice melt increases
- Surface albedo decreases
- More insolation is absorbed
- Temperatures increase
What is an example of negative feedback?
- Temperatures increase
- Permafrost cover decreases
- Increased growth of photosynthesisers
- More CO2 is sequestered
- Greenhouse Effect reduced
What is dynamic equilibrium within a glacial system?
A state of balance caused by the continual processes of accumulation and ablation.
What is the equilibrium line?
The point on a glacier where accumulation = ablation.
