Lecture 3 - Snow and the Cryosphere Flashcards
Briefly describe high arctic
northern tundra vegetation very short bare ground less snow or wind no winter thaw/winter deser
Briefly describe low arctic
southern part of tundra complete vegetation cover patches of shrubs lots of snow and wind can have winter thaw
briefly describe subarctic
- climatologist
- biologist
C: mean teams >10 for months
B: forests and permafrost
Define the cryosphere
portion of the earth where water is in solid form
ex. frozen ground, glaciers, snow cover, sea ice
What 3 factors have the largest influence on frozen ground?
Temperature
Seasonality
Latitude
~ also local landscapes
list various forms of landscape features that impact frozen ground
soil type lakes/rivers snow slopes wind direction plants peat
define peat plateaus
flat-topped areas of peat
define palsas
low frost leaves that contain permanently frozen ice lenses
- stick up above surrounding land exposing sides and top of air
how long does ground need to be frozen to be considered permafrost?
2 years
what is the active layer?
layer above permafrost that has seasonal thawing and freezing
Define Talik
soil or unfrozen ground above or within permafrost
How does permafrost expand/grow year after year? what is thickness dependent on?
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`
What are the 2 types of permafrost?
- Continuous
2. Discontinuous
What are the differences between the 2 types of permafrost?
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
What is subsea permafrost?
How did it form?
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
How does permafrost impact the landscape?
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
define pingo
subsurface water can freeze and force frozen ground upward to form cone-shaped mounds with cores of ice
what is the difference between bingos and palsas?
pingos: ground below the active layer TF much bigger
palsas: IN active layer
what does albedo refer to?
% of solar energy reflected back into space
what is albedo influenced by?
snow depth, clouds, soil, location, age, pollution
how does the albedo change between fresh snow and water?
snow = 90%
water = 5%
- darker tf absorbs more
what is arctic amplification
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
what are types of snowpack formation?
destructive metamorphism
constructive metamorphism
what factors play a big role in snowpack formation
wind
occurrence of winter thaws
