Lecture 3 - Snow and the Cryosphere

Question 1

Briefly describe high arctic

Answer 1

northern tundra
vegetation very short
bare ground
less snow or wind
no winter thaw/winter deser

Question 2

Briefly describe low arctic

Answer 2

southern part of tundra
complete vegetation cover
patches of shrubs
lots of snow and wind
can have winter thaw

Question 3

briefly describe subarctic

• climatologist
• biologist

Answer 3

C: mean teams >10 for months
B: forests and permafrost

Question 4

Define the cryosphere

Answer 4

portion of the earth where water is in solid form

ex. frozen ground, glaciers, snow cover, sea ice

Question 5

What 3 factors have the largest influence on frozen ground?

Answer 5

Temperature
Seasonality
Latitude
~ also local landscapes

Question 6

list various forms of landscape features that impact frozen ground

Answer 6

soil type
lakes/rivers
snow
slopes
wind direction
plants
peat

Question 7

define peat plateaus

Answer 7

flat-topped areas of peat

Question 8

define palsas

Answer 8

low frost leaves that contain permanently frozen ice lenses

- stick up above surrounding land exposing sides and top of air

Question 9

how long does ground need to be frozen to be considered permafrost?

Answer 9

2 years

Question 10

what is the active layer?

Answer 10

layer above permafrost that has seasonal thawing and freezing

Question 11

Define Talik

Answer 11

soil or unfrozen ground above or within permafrost

Question 12

How does permafrost expand/grow year after year? what is thickness dependent on?

Answer 12

active layer freezes in winter and thaws in summer (top-down)
when active layer thaws, water can’t drain through permafrost.
depends on summer temp and soil parent material`

Question 13

What are the 2 types of permafrost?

Answer 13

1. Continuous

2. Discontinuous

Question 14

What are the differences between the 2 types of permafrost?

Answer 14

Cont: occurs under almost all land surfaces, except beneath large water bodies (often >100m thick)
occur far north/high arctic
Discount: occurs 50-90% of land area, sporadic (up to 10m thick)
occur in southern regions

Question 15

What is subsea permafrost?

How did it form?

Answer 15

under arctic ocean
formed during last ice age when there was a lower sea level and exposed land froze.
when ice sheets melted, sea level rose and covered areas of permafrost

Question 16

How does permafrost impact the landscape?

Answer 16

cracks
pushes soil up
polygons can form
lakes can form
depressions formed when permafrost thaws and soil collapses
high-entree polygons and thermokarst lakes
connected pons
pingos

Question 17

define pingo

Answer 17

subsurface water can freeze and force frozen ground upward to form cone-shaped mounds with cores of ice

Question 18

what is the difference between bingos and palsas?

Answer 18

pingos: ground below the active layer TF much bigger
palsas: IN active layer

Question 19

what does albedo refer to?

Answer 19

% of solar energy reflected back into space

Question 20

what is albedo influenced by?

Answer 20

snow depth, clouds, soil, location, age, pollution

Question 21

how does the albedo change between fresh snow and water?

Answer 21

snow = 90%
water = 5%
- darker tf absorbs more

Question 22

what is arctic amplification

Answer 22

how the arctic is warming twice as fast as the rest of the planet

changing from high relative surface area to dark surface. so sun that would normally be reflected back into the atmosphere is being absorbed

Question 23

what are types of snowpack formation?

Answer 23

destructive metamorphism

constructive metamorphism

Question 24

what factors play a big role in snowpack formation

Answer 24

wind

occurrence of winter thaws

Question 25

describe destructive metamorphism

Answer 25

“destruction” of individuals grains of snow as it settles
- decreases volume
- increases density
occurs early when snow settles

Question 26

describe constructive metamorphism

Answer 26

new crystals form as water vapour rises moving from warmer areas near ground

• water vapour crystallizes as it hits colder temps
• greater temp gradient = more vapour is transferred

Question 27

Describe the Depth Hoar

Answer 27

coarsest grains of snow usually found near the soil surface (sugar snow)
- poorly bound
- forms subnivian zone (below snow)
destabilizes snow = avalanches

Question 28

Does constructive and destructive metamorphism occur separately?

Answer 28

No, simultaneously

Question 29

with new snow, does constructive or destructive dominate?

Answer 29

destructive

Question 30

with old snow, does constructive or destructive dominate?

Answer 30

constructive

Question 31

what is “corn snow” how is it formed?

Answer 31

when meltwater/rain water enters snowpack, there is increased vapour migration and freezing - leading to large rounded grains
- creates layers in snow

Question 32

What can cause layers in snow?

Answer 32

wind - increase wind, increased convection
water vapour - vapour gradient btwn snow and air
radiation - shortwave/longwave
advected heat - rain
soil contact - convection

Question 33

qualities of snow cover affecting living organisms

Answer 33

1 duration
2 thickness
3 hardness
4 density

Question 34

3 components of the novena environment

what uses each?

Answer 34

1 subnivean
- small mammals in depth hoar
2 intranivean
- ruffed grouse, burrowing
3 supranivean
- lynx, on top

Question 35

how does ice prevent ocean from warming?

Answer 35

high albedo of ice/snow reflects solar energy rather than absorbing

Question 36

what is “fast ice”

Answer 36

ice in coastal regions where it grows and remains attached to shore

Question 37

what are the principal forces acting on sea ice in order of importance?

Answer 37

wind
ocean currents
Coriolis force
Internal ice stress
Sea surface tilt

Question 38

how does sea ice formed from salt water cause ocean currents?

Answer 38

salt doesn’t freeze = increase salinity at surface, water gets dense and sinks to lower level

Question 39

define polynyas

Answer 39

persistent open water surrounded by ice

Question 40

define Biomes

Answer 40

major geographical areas characterized by a particular type of flora and fauna - primarily determined by climate