Cryosphere 1- introduction

Question 1

What are the main general parts of the atmosphere?

Answer 1

Snow
Sea ice
Ice shelves
Ice sheets
Glaciers and ice caps
Permafrost continuous
Permafrost discontinuous, isolated

Question 2

What are the timescales for lifetime/ rate of change in different parts of the cryosphere?

Answer 2

Snow - day to month (seasonal)
River and lake ice - seasonal
Glaciers and ice caps- seasonal to century
Frozen ground- daily to millennium
Ice sheet margin- monthly
Ice shelves- yearly
Ice sheet- millennium

Question 3

What are the 2 present day ice sheets in the cryosphere?

Answer 3

Greenland
Antarctic

Question 4

Where can permafrost be found?

Answer 4

Siberia
Northern Russia
Northern north America

Question 5

What is permafrost?

Answer 5

permanently frozen ground at a certain depth

Question 6

What is the active layer when considering permafrost?

Answer 6

the top most layers that will experience seasonal freezing and thawing

Question 7

What can lead to the changing of lifespan for different parts of the crysosphere?

Answer 7

climate forcing - warming, cooling, changing weather patterns

Question 8

What affects how quickly a reservoir will react with the environment?

Answer 8

the size of reservoir

Question 9

What would happen to sea level if the Greenland ice sheet instantly melted?

Answer 9

would rise by around 8m

Question 10

What would happen to sea level if the Antarctic shelf melted instantly?

Answer 10

50 m rise

Question 11

What is the last largest ice sheet which is no longer present?

Answer 11

the Laurentide

Question 12

Where was the Laurentide ice sheet located?

Answer 12

North America extended past New York and Mid-west to Rockies

Question 13

How has ppm of CO2 changed over time? (numbers)

Answer 13

present day - 420
Pre Industrial revolution - 280
Last glacial maximum - 180

Question 14

How much lower was sea level 22 Ka?

Answer 14

180m lower at max ice sheet size
120m average for ice age (last 80 Ka)

Question 15

Why was sea level lower in the last glacial maximum?

Answer 15

the water becomes locked in ice sheets

Question 16

What happens when a continental ice sheet becomes large enough?

Answer 16

pushes to edge of continental land then land dips down leading ice to float on top of the water

Question 17

What does ice that floats on water form? (when still attached to main ice sheet)

Answer 17

Ice shelves

Question 18

What is ice berg calving?

Answer 18

ice berg creation this is when ice breaks off from the edge of the ice shelf

Question 19

What will the stability of floating ice generally be like?

Answer 19

Inherently unstable

Question 20

What is buttressing with ice shelves?

Answer 20

how the ice shelf interacts with the topography beneath it especially high points

Question 21

What can happen to ice contact with underlying topography is there is any rise in sea level?

Answer 21

ice lifted off these points causing fractures and breaks increasing melting risk from both sides ocean below and atmosphere above

Question 22

Why are strong Katabatic winds present in the Antarctic?

Answer 22

due to change in altitude and temperature regional density currents are created

Question 23

What is the effect of the strong Katabatic winds on the ice shelfs and ice margin environment?

Answer 23

push sea ice away from ice shelf
creating an open water area

Question 24

How do katabatic winds lead to upwelling?

Answer 24

winds create current which pushes surface water away by wind meaning deep nutrient rich water rises to take place

Question 25

What do ice streams do to the energy in ice sheets?

Answer 25

focus energy allowing movement of ice in plastic form Act as river system bringing ice mass to edge

Question 26

When did the Larsen B ice shelf break up?

Answer 26

98-01

Question 27

What were the stages that lead to the break up of Larsen B?

Answer 27

Cracks appeared which filled with meltwater leading to huge calving event (explosion/ shattering of shelf)

Question 28

What problems arise form large ice shelves like Larsen B breaking up?

Answer 28

expose land ice behind making calving and melt more likely which can significantly affect sea level

Question 29

What are the 2 main types of mountain glacier?

Answer 29

Cirque Valley

Question 29

What is a cirque?

Answer 29

circular bowl shape cut into mountain side

Question 30

What is an arete?

Answer 30

when two headwalls of cirque erode back to back creating a knife edge ridge

Question 31

What can lead to the formation of a pyramidal peak?

Answer 31

3 or more cirques erode back to back creating a steep pointed peak

Question 32

What is the transition of mountain glaciers like?

Answer 32

Cirque will flow into a small valley glacier which will in turn flow into the main valley glacier

Question 33

What is an examples of a valley glacier?

Answer 33

Franz Josef New Zealand

Question 34

What will valley glaciers do to the surrounding valley?

Answer 34

erode and smooth it down creating a U-shaped valley

Question 35

What do U shaped valleys provide a visual reminder of in the UK?

Answer 35

Glaciated past of the British isles

Question 36

What is a piedmont glacier?

Answer 36

when the valley ends and the glacier flows into an open lowland area it will spread out showing how glaciers can be plastic (weight and heat)

Question 37

What is an example of a piedmont glacier?

Answer 37

elephant foot glacier Greenland

Question 38

What is a nunatak?

Answer 38

when some of the mountainous topography sticks out the top of the glacier

Question 39

How can you tell nunataks from the surrounding rock?

Answer 39

as they lie above the glacial erosivity line they are instead affected by freeze thaw for will be weak/ easier to break with hammer

Question 40

How much of fresh snow is air? (first stage glacial ice formation)

Answer 40

90%

Question 41

What will happen to fresh snow with continual compaction?

Answer 41

it will transition into firmer more dense layers until glacial ice is formed

Question 42

How much air is in granular ice? (2nd stage of glacial ice formation)

Answer 42

50%

Question 43

How much air is in firn? (3rd stage og glacial ice formation)

Answer 43

20-30%

Question 44

How much air/ air bubbles are present in glacial ice?

Answer 44

20%

Question 45

At what rate does Greenland ice accumulate?

Answer 45

50cm yr-1

Question 46

At what rate does Antarctica ice accumulate?

Answer 46

5cm yr-1

Question 47

How can seasonal variation be seen in ice cores?

Answer 47

will be a darker summer layer and lighter winter layer which form one year

Question 48

What is the important factor that can be measured in ice cores?

Answer 48

The gas bubbles they contain can be radiometrically dated to used to analyse past climate composition

Question 49

What is an archive?

Answer 49

record of information (not how stored just where)

Question 50

What are ice archives key evidence of the connection between in?

Answer 50

the atmosphere

Question 51

What past variables can be found through ice cores?

Answer 51

Temp CO2 Dust

Question 52

How might the Milankovitch cycles link to the saw tooth pattern of past temperature?

Answer 52

Cooler interglacial 100 Ka cycle maybe linked to eccentricity warmer interglacial 40 Ka time scale maybe linked to obliquity 20 Ka peaks in these period procession

Question 53

What was pre-industrial CO2 PPM like?

Answer 53

180-280ppm 100ppm range due to sheet shift and sea level change

Question 54

Why is dust concentration typically higher in glacial periods?

Answer 54

due to colder air which can hold less moisture/ water vapour- dry atmosphere- dust production

Question 55

What is glacial mass balance?

Answer 55

the balance between input and output from a glacier

Question 56

What is the zone of accumulation?

Answer 56

area of added mass to a glacier accumulation greater than ablation Usually lighter due to fresh snow

Question 57

What is the zone of ablation?

Answer 57

greater ablation than accumulation Darker/ dirty due to material present Where loss of glacial mass occurs

Question 58

How do glaciers move?

Answer 58

Combination of 3 factors: 1&2) internal flow in solid ice 3) Sliding along the base

Question 59

What type of glacier is internal flow more common in?

Answer 59

cold based glaciers as the ice is stuck to the bedrock

Question 60

What basic physics is internal flow defined by?

Answer 60

thickness density acceleration sin/ angle of slope

Question 61

What counteracts internal flow?

Answer 61

friction

Question 62

How do warm based glaciers predominantly move?

Answer 62

basal slip where water acts as lubrication between rock and ice (meltwater produced as PMP lowers melt temp slightly)

Question 63

What temp of ice will cold glaciers be made of?

Answer 63

only cold ice which is very strong and well below freezing point

Question 64

What will warm glacial ice co-exist with?

Answer 64

water at pressure melting point

Question 65

What is pressure melting point?

Answer 65

when the melting point is lowered under a column of ice

Question 66

What temp of ice are temperate glaciers made of?

Answer 66

only warm ice apart from top 10-15m in winter

Question 67

What are polythermal glaciers?

Answer 67

they have both warm and cold ice

Question 68

What allows water to move around the glacial system?

Answer 68

complex plumbing system of supra and sub glacial streams combined with moulins and supraglacial ponds

Question 69

What is the problem with the formation of melt-ponds in the supraglacial environment?

Answer 69

Darker low albedo go through 90 to 10% reflected feeds positive feedback

Question 70

What is the problem with meltwater ponds and moulin production?

Answer 70

Meltwater can sink and erode its way through the glacial ice creating a hole/ channel to the sub-glacial environment allowing vast amounts of meltwater to base lifting glacier making movement easier and shifting more mass to ablation zone.

Question 71

How can deforming beds be a way of glacial movement?

Answer 71

if sediment under glacier instead of rock they will deform faster so less obstruction to movement