L3 - Glacer Mass Balance

Question 1

What does accumulation at high elevations do?

Answer 1

Add Mass

Question 2

What does ablation at low elevations do?

Answer 2

Remove Mass

Question 3

What is Mass Balance?

Answer 3

The difference between mass gains and mass losses (it can be +ve or -ve)

Question 4

What 3 things is glacier mass balance a function of?

Answer 4

1. Climate
2. Local Topography
3. Glacier Hypsometry

Question 5

What is Hypsometry?

Answer 5

Area to Elevation Ratio

Question 6

Give 4 processes of accumulation

Answer 6

1. Snowfall
2. Wind Drift
3. Avalanching
4. Meltwater Freezing (Rimming & Superimposed Ice)

Question 7

Give 4 processes of ablation

Answer 7

1. Surface and/or basal melting
2. Sublimation
3. Avalanching
4. Calving (Wet or Dry)

Question 8

What is Sublimation?

Answer 8

The move from a Solid to a Gas

Question 9

What is Calving?

Answer 9

The process by which ice breaks off a glacier terminus

Question 10

What are processes of accumulation and ablation important for?

Answer 10

Budgets

Question 11

What are the 4 zones within the accumulation zone (in order - starting furthest from the ELA)?

Answer 11

1. Dry Snow Zone
2. Percolation Zone
3. Wet Snow Zone
4. Superimposed Ice Zone

Question 12

In which accumulation zone do you get firn?

Answer 12

The Percolation Zone

Question 13

What is the ELA?

Answer 13

The Equilibrium Line Altitude - the point where ablation = accumulation

Question 14

What causes the ELA to vary?

Answer 14

Glacier type, morphology, location, time of year and hypsometry

Question 15

Why is the ELA an indicator of glacier health?

Answer 15

The more downhill it is, the more accumulation there is, hence a healthy glacier

Question 16

What are the 3 types of glacier than can be determined from the balance year curve?

Answer 16

1. Winter Accumulation Type
2. Summer Accumulation Type
3. Year Round Ablation Type

Question 17

What is specific net balance?

Answer 17

Net changes in mass at one point

Question 18

What is cumulative net balance?

Answer 18

Running total of net balance since measurements began

Question 19

What is net balance?

Answer 19

Difference between mass balance minima

Question 20

Why do you get mass balance gradients?

Answer 20

Because rates of accumulation and ablation change with altitude

Question 21

What does a high mass balance gradient mean?

Answer 21

High mass through flow

Question 22

What 4 things do you need to know in order to determine mass balance?

Answer 22

1. Mass Accumulation
2. Ice Discharge from Ice Streams & Outlet Glaciers
3. Surface Melt
4. Hypsometry

Question 23

What are the 5 methods that are used to measuring mass balance?

Answer 23

1. Direct Measurements (Pits & Stakes)
2. Hydrological Measurements of Q
3. Weighing the Ice
4. Remote Sensing
5. +ve Degree Days

Question 24

What are the issues associated with manual measurements of mass balance?

Answer 24

Expensive, dangerous, time-consuming and poor spatial coverage

Question 25

What are the issues associated with remote measurements of mass balance?

Answer 25

Ground truthing will always be required and there is poor spatial coverage (Hole at the Pole)

Question 26

When the World Glacier Monitoring Service begin?

Answer 26

1984

Question 27

What does World Glacier Monitoring Service focus on in its annual reports?

Answer 27

ELA, net balance, cumulative net balance and accumulation area ratios (AAR)

Question 28

Where are the 2 places that have seen advance since the 1990s?

Answer 28

1. Western Norway

2. Patagonia

Question 29

Where has seen retreat?

Answer 29

1. The Alps
2. Asia and The Tropics
3. New Zealand

Question 30

What 6 things impact mass balance?

Answer 30

1. Methods of Mass Addition
2. Methods of Mass Loss
3. Climate
4. Ice Sheet Instability
5. Iceberg Calving
6. Changes in Ice Dynamics