Glaciers (mostly)

Question 1

average yearly slr

Answer 1

3.5 - 4 mm/ yr

Question 2

how many glaciers on earth

Answer 2

over 270 000

Question 3

geodetic method of measuring glacier mass change

Answer 3

looks at elevation change, and calculates mass change using density assigned to firn, ice and snow

Question 4

gravimetric method

Answer 4

using GRACE sat, measures direct mass change
coarse resolution
difficult to seperate from different mass change signals such as hydrological storage and GIA

Question 5

how much land surface do glaciers cover

Answer 5

700 000 square km (0.5%)

Question 6

What is the sea level equivalent of total glacier ice

Answer 6

0.41 m (170 000 cubic km)

Question 7

mass balance

Answer 7

difference between the amount of ice and snow gained and lost by a glacier over a period of time

Question 8

gigatonne

Answer 8

1 x 10^12 (1 cubic km of water)

Question 9

How much ice melt needed to raise sea level by 1mm

Answer 9

361.8 Gt

Question 10

Specific mass balance

Answer 10

mass lost or gained per unit area often in kg/m^2 or m.w.e (Metre Water Equivalent)

Question 11

Sublimation

Answer 11

When solids transition directly to gas - occurs in ablation zone

Question 12

what are the 2 drivers of Antlantification of the arctic?

Answer 12

atmospheric forcing and ice ocean interaction

Question 13

Dynamic process of mass loss

Answer 13

involves ice - ocean interaction as opposed to surface process of mass loss

Question 14

What is the percentage contribution of surface processes to global glacier mass loss?

Answer 14

90%
The remaining 10% is attributed to dynamic processes

Question 15

What region is the largest global contributor of glacier mass loss?

Answer 15

Alaska - mostly due to atmospheric forcing

Question 16

What process contributes the most to mass loss in mass loss in Patagonia

Answer 16

Neither, It’s roughly a 50/50 split between dynamic and surface processes
- Dynamic is mostly due to the Patagonian ice field and proglacial lakes

Question 17

What is the trend of hypsometric control on glacier mass change?

Answer 17

At higher elevations there is less change

Question 18

What is the number one contributor to slr in the cryosphere

Answer 18

glaciers

Question 19

what is ASTER remote sensing

Answer 19

stereo photogrammetry

Question 20

What does cryosat use

Answer 20

radar altimetry

Question 21

What does icesat use?

Answer 21

lazer altimetry

Question 22

What are models useful for

Answer 22

determining which physical processes are the most responsible for observed behaviour

Inferring quantities that are not directly observable

Question 23

Forms of accumulation on glaciers

Answer 23

snowfall,
deposition of hoar/ freezing rain,
gain of snow by wind,
avalanching,
basal freeze,
internal accumulation/ refreezing

Question 24

Forms of ablation

Answer 24

Melting,
calving,
wind blowing snow off glacier
avalanching
sublimation

Question 25

What does an increase in ELA lead to?

Answer 25

Glacier retreat

Question 26

What is the climatic snowline?

Answer 26

Approximate elevation where snowfall matches melting, glaciers expected at this altitude if there is land

Question 27

What are the two main processes that make glaciers thicken/ thin?

Answer 27

Change in surface mass balance and changes in flow rate

Question 28

What are the differences between Karakoram and the rest of the Himalayas?

Answer 28

Karakoram is much colder, receives most of its snow in winter compared to summer for HMA, they are affected by different large scale winds, debris cover higher in karakoram,

Question 29

What influence does debris on glacier have on albedo?

Answer 29

it lowers it

Question 30

What are the 5 main fluxes in the Surface Energy Mass balance?

Answer 30

Short wave radiation Longwave radiation Sensitive (mixing) heat flux Latent heat flux Diffusion into deeper snow and ice

Question 31

define flux

Answer 31

amount of energy crossing a surface by unit area

Question 32

Degree day models

Answer 32

based on assumed relationship between ablation and air temperature (usually expressed in the form of positive temperature sums)

Question 33

Degree Day Factor (DDF)

Answer 33

amount of melt that occurs per positive degree day

Question 34

What basically occurs when glaciers surge

Answer 34

they thin and lengthen

Question 35

When does glacier surging occur

Answer 35

this happens when meltwater cannot drain from the base easily due to ice becoming too thick This is because the lack of meltwater leads to a heating up of the base, resulting in thermal surging occurs when there is

Question 36

What are the stages of the surging cycle?

Answer 36

thickening, pressurising, surging, thinning

Question 37

How does glacier ice density generally change with depth?

Answer 37

Ice density increases