1.a. Glaciated landscapes can be viewed as systems

A conceptual overview of: 1-the components of glaciated landscape systems, including inputs, processes and outputs 2-the flows of energy and material through glaciated systems 3-glacier mass balance.

What type of system are glaciers

Open

Inputs, outputs, and processes can be either in the form of ___ or ____

Materials, energy

Inputs to glaciers (materials)

Precipitation, snow, avalanche debris, rock debris

Inputs to glaciers (energy)

Gravity, solar radiation, geothermal heat

Processes to glaciers (materials)

Glacial movement, sediment transport, erosion

Processes to glaciers (energy)

Melting, sublimation, evaporation

Outputs to glaciers (materials)

Meltwater, water vapour, ice falls, icebergs, sediment

Outputs to glaciers (energy)

Heat from friction

Sublimation

When substances go directly from solid to gas

Accumulation

All processes that add to the volume of the glacier

Ablation

All the processes that reduce the volume of the glacier

Annual mass balance

The mass balance at the end of the year

How is annual mass balance calculated

The sum of the winter balance and the summer balance

Stores

The moving ice and material, within, upon and underneath the glacier. It forms from the compacted snow

Equilibrium

When the inputs / accumulation and outputs / ablation are equal, a state of equilibrium exists

What happens when equilibrium is disturbed

The system undergoes self regulation until the equilibrium is restored

Dynamic equilibrium

When the system undergoes self-regulation to restore the equilibrium. It is called dynamic equilibrium because the system is producing its own response to disturbance

What is dynamic equilibrium an example of

Negative feedback

Example of self-regulation

Glacier gets too heavy -> avalanche occurs -> sediment is lost

What determines how glaciers grow or retreat

The balance between accumulation and ablation.

When is mass balance positive

If more snow accumulates in the winter than is lost in the summer

When is mass balance negative

If the summer melting exceeds the accumulation in the previous winter

Flows of energy in glaciated systems

Potential energy from elevation, kinetic energy from ice movement, thermal energy from solar radiation, friction and geothermal heat

Flows of material in glaciated systems

Ice movement, meltwater flow, sediment erosion, transport, and deposition

Transfers in glaciated systems

Sediment is moved from one part of the glacier to another; energy is transferred as ice moves downslope

What is the ablation zone of a glacier

The lower part of a glacier where melting, sublimation, and calving reduce ice mass

What is the equilibrium line on a glacier

The line separating accumulation and ablation zones where annual accumulation equals ablation

Seasonal variation in glacier mass balance

Winter = accumulation predominates; Summer = ablation predominates; net annual balance determines whether glacier grows or retreats

Example of a glacier with clear accumulation and ablation zones

Mer de Glace, France — snow accumulates in upper zones; ice melts in lower zones

Example of self-regulation in a glacier

Glacier gets too heavy in accumulation zone → avalanche occurs → excess sediment is removed → system restores dynamic equilibrium

Example of negative feedback in a glacier

If glacier snout advances too far → increased melting at lower elevations slows growth → system regulates itself

Example of energy and material flows in a glacier

Greenland ice sheet — ice moves downslope (material), friction generates heat (energy), meltwater transports sediment (material flow)

What is the accumulation zone of a glacier

The upper part of the glacier where snowfall adds to ice mass