Glacier mass balance Flashcards
Define the term mass balance?
The mass balance of the glacier refers to the balance between the inputs and outputs of a glaciers.
Define the term accumulation?
Accumulation refers to the collective gain in an ice mass by processes such as snowfall, avalanches and the refreezing of meltwater.
Define the term ablation?
Ablation refers to the collective loss of water from a glacier by processes such as surface melting, evaporation and sublimation.
What is one of the main roles of glaciers?
All glaciers, from the smallest cirque glaciers to the largest ice sheets, are conveyors of ice, transporting it from areas of net input (the accumulation zone) to areas of net output (the ablation zone).
When is the glacier said to be in a steady state?
Where accumulation and ablation are equal, the glacier is said to be in a steady state with a mass balance of zero.
Why do glaciers rarely have a mass balance of zero?
- Changes in the global environmental systems influence the balance of inputs and outputs of a glacier
Why is the balance between inputs and outputs constantly changing?
The balance between accumulation and ablation changes seasonally and annually. It also varies along the glaciers length.
What does it mean if a glacier has a positive budget?
If a glacier has a positive budget, it means that the volume of inputs exceeds the volume of outputs and the glaciers mass is increasing.
What does it mean if a glacier has a negative budget?
The glacier has a negative budget when the volume of outputs exceeds the volume of inputs and the glaciers mass is decreasing.
When do glaciers have a positive budget?
Glaciers usually have a positive budget in winter and during periods of climatic cooling.
When do glaciers have a negative budget?
Glaciers usually have a negative budget in summer or during periods of climatic warming.
What happens to the movement of ice when a glacier is shrinking?
Even when a glacier is shrinking, ice still moves forward under its own weight and gravity from the accumulation zone to the ablation zone.
What is the accumulation zone and the ablation zone separated by?
The accumulation zone and the ablation zone is separated by the equilibrium line.
What is the equilibrium line?
The equilibrium line is where there is a balance of inputs and outputs.
