5.1: The operation of a glacier system

Question 1

Define what Glacial mass balance is

Answer 1

the gains and losses of the ice store in the glacier system

Question 2

Define Ablation

Answer 2

Ablation refers to all processes that remove mass from a glacier.

Question 3

Define Accumulation

Answer 3

All the process’ that add mass to a glacier results from direct snowfall and other precipitation, ice, blown snow and avalanches

Question 4

Name 2 ways a glacier looses mass through ablation

Answer 4

1. melting
2. evaporation (sublimation)
3. break away as ice block or ice bergs (calving)

process’ collectively called ablation

Question 5

In a glacial system where do you get more accumulation than ablation

Answer 5

in the upper part of the glacier

Question 6

What is the name for the place where accumulation and ablation balance each other out

Answer 6

the equilibrium point

Question 7

If accumulation exceeds ablation the glacier …? in mass

Answer 7

Increases

Question 8

In the summer where there is more ablation than accumulation the glacier had a …? regime in the glacial budget.

Answer 8

Negative

Question 9

If the accumulation in winter is equalled by the ablation in summer, then the annual net balance is …? and the glacier is at a constant

Answer 9

0

Question 10

A positive regime or mass balance causes the glacier to…

Answer 10

grow and therefore the snout advances

Question 11

A negative regime or mass balance causes the glacier to…

Answer 11

thin and shrink and therefore the position of the snout begins to retreat

Question 12

A drop in temperature leads to an increase in ice cover and increases the albedo effect leading to a drop in temperature, increased ice cover and even further increased albedo

What kind of feedback loop is this? Name it

Answer 12

Positive

Question 13

If there is an increase in solar radiation and an increase in temperature, this leads to ice melt and reduced albedo leading to further increase in temperature

What kind of feedback loop is this? Name it

Answer 13

Positive

Question 14

Name 3 process’ of accumulation of a glacier

Answer 14

1. Direct snowfall - snow falling directly onto the surface of a glacier
2. avalanches - debris and snow being deposited onto the glacier via this
3. wind deposition - sediment and snow is blown onto the glacier
4. rain
5. hail

Question 15

Name 3 process’ of ablation of a glacier

Answer 15

1. melting
2. sublimation - the conversion between the solid and the gaseous phases of matter, with no intermediate liquid stage
3. calving - the breaking of ice chunks from the edge of a glacier
4. evaporation
5. avalanches

Question 16

Since the industrial revolution the levels of C02 in the atmosphere has dramatically increased leading to an increase in temperatures.

What effect has this had on glaciers

Answer 16

They have retreated

Question 17

Describe the fluctuation of glaciers in South Georgia.

1. what further happened 3600 and 1100 years ago?
2. When was there glacial readvancement?
3. What has happened at Gold Harbour in the modern day?

Answer 17

1. there was notable glacial retreat
2. between 1925 - 1935
3. the lowest section of the Bertrab glacier has disappeared entirely, exposing a large rock step which 30 years ago was covered by ice

Question 18

How do you calculate glacial mass balance

Answer 18

Mass balance (b) is the product of accumulation (c) plus ablation (a)