Glaciation - Unit 1

Question 1

What is a glacier?

Answer 1

A moving body of ice

Question 2

What is a system?

Answer 2

Consists of inputs, outputs, stores and transfers

Question 3

Why might a glacier be considered a system?

Answer 3

It is considered a dynamic system as it’s in a constant state of flux

Question 4

How are glaciers formed?

Answer 4

• Snowflakes fall (density = 0.1gm/cc + contain air)
• Collects in hollows
• Begins to compact
• Forms neve (compacted snow that has experienced 1yr of freezing and melting)
• Summer meltwater percolates into neve
• Becomes more dense when it refreezes
• Air is squeezed out
• After a number of years, a glacier can form (density = 0.9gm/cc)

Question 5

What is a positive balance?

Answer 5

When Inputs are greater than outputs so glacier advances

Question 6

What is a negative balance?

Answer 6

When outputs are greater than inputs so glacier retreats

Question 7

Inputs?

Answer 7

Snowfall

Avalanches

Question 8

Outputs?

Answer 8

Evaporation
Sublimation
Meltwater

Question 9

Ablation?

Answer 9

Natural removal of snow/ice from surface of glacier

Question 10

Accumulation?

Answer 10

Build up of glacier and snow is compacted into ice

Question 11

Calving?

Answer 11

Splitting end of glacier into smaller sections

Question 12

Glacial budget?

Answer 12

Mass balance - determines if glacier will advance/retreat

Question 13

Accumulation zone?

Answer 13

Located at head of glacier

Inputs > outputs over 1 year

Question 14

Equilibrium zone?

Answer 14

Located at centre of glacier

Inputs = outputs over 1 year

Question 15

Ablation zone?

Answer 15

Located at snout of glacier

Inputs < outputs over 1 year

Question 16

What are the short term changes to mass balance?

Answer 16

Annual changes

Anthropogenic climate change

Question 17

What are the long term changes to mass balance?

Answer 17

Natural climate variations

Question 18

What are some of the potential changes for our planet in the next 100 years?

Answer 18

• CO2 levels increase by almost 200ppm
• Average temp increase by 2°C
• Sea level increase by almost 5m

Question 19

How does positive feedback affect the glacial mass balance system?

Answer 19

Snow and ice cover-

If it increases:

• Raises surface albedo (reflectivity of Earth’s surface)
• More solar energy reflected back into space
• Further cooling
• More snow/ice cover

If it decreases;

• Lowers surface albedo
• Less solar energy reflected back into space
• Increases heating
• Permafrost melts and methane is released
• Less snow/ice cover

Question 20

How does negative feedback affect the glacial mass balance system?

Answer 20

Increase in our current global warming trend leads to increased evaporation from oceans = more cloud cover
Cloudy skies reflect more incoming solar energy
Decrease in global warming = decrease in melting ice cover