L16: Cryosphere pt. 1

Question 1

Cryosphere

Answer 1

• the part of the Earth’s surface that remains perennially frozen, which is about 1/3 of the surface of the Earth.
• The cryosphere does not include areas that are temporarily covered by snow or ice, although these are important contributors to the hydrologic cycle.

Question 2

Where is the cryosphere located?

Answer 2

primarily located near the North and South poles, and at higher elevations

Question 3

Albedo

Answer 3

highly reflective surface; sunlight bounces back into space, reducing surface temperatures

Question 4

Snowlines

Answer 4

marks boundary of areas that have snow year-round. Its location is controlled by variations in thickness of winter snowpack and local topography, with its altitude typically changing from year to year depending on winter snow accumulation and summer melting

Question 5

What are the 2 primary ways snowline varies?

Answer 5

(1) it is at lower elevation in polar areas where temperature is colder, and
(2) it is lower in coastal areas where there is more moisture and thus more snow

Question 6

How is firn formed?

Answer 6

• Existing snow is compacted by newer overlying snow, and evaporation occurs at the points of snowflakes. Moisture freezes between points forming a granular snow called firn. Firn gradually loses interstitial air to become ice. As depth and time increase, the grains of ice become larger due to recrystallization.

Question 7

Glaciers

Answer 7

Above the snowline, snow accumulates to form ice. Ice masses that flow under the influence of gravity

Question 8

Where is flow the fastest in glacial ice? Where is it the slowest?

Answer 8

fastest at the center of the glacial channel, and slowest at the edges due to friction with the bed

Question 9

Cold glaciers

Answer 9

• Cold (or polar) glaciers do not flow at their base. This causes cold glaciers to typically have a cliff terminus.
• are frozen onto the underlying bedrock and therefore do not slide

Question 10

Warm glaciers

Answer 10

• Warm (or temperate) glaciers have meltwater at their base, which allows for flow along the bedrock. This causes warm glaciers to typically have a rounded terminus (or toe).
• movement occurs both due to internal flow and sliding at the base

Question 11

Why are glaciers able to flow?

Answer 11

because the ice crystals that comprise it deform under stress. The continued deformation of these crystals causes the alignment of ice crystal structures

Question 12

Regions of accumulation

Answer 12

where mass is added

Question 13

Regions of ablation

Answer 13

where ice mass is lost

Question 14

What can cause ablation?

Answer 14

(1) melting
(2) evaporation
(3) calving – the breaking off of ice from the parent glacier

Question 15

When do ablation and accumulation exceed each other?

Answer 15

Accumulation typically exceeds ablation in the upper part of a glacier, while ablation exceeds accumulation in the lower part

Question 16

How are ablation and accumulation areas separated?

Answer 16

Accumulation and ablation areas of a glacier are separated by an equilibrium line. The overall ice mass balance of a glacier is equal to its accumulation minus ablation.

Question 17

A glacier with ________ mass balance is receding

Answer 17

Negative

Question 18

Chatter marks

Answer 18

crescent-shaped gouges that can form as rock fragments are dragged across bedrock by a glacier

Question 19

Striations

Answer 19

linear gouges or scratches left in bedrock by glaciers as they move sand and rock fragments at their base

Question 20

U-shaped valleys

Answer 20

steep sides and broad, flat bottoms are a typical erosional landforms left by glaciers

Question 21

Hanging valleys

Answer 21

often present at higher elevation and feed into U-shaped valleys as tributaries

Question 22

Erosional features

Answer 22

• Arêtes are sharp-edged ridges
• Cirques are bowl-shaped valleys formed at a glacier’s head
• Horns are pointed pyramidal peaks