glaciation eq1

Question 1

what is an interstadial period?

Answer 1

short periods of intense warmth

Question 2

what is a stadial period?

Answer 2

short periods of intense cold

Question 3

what are long term causes of glacial and interglacial cycles?

Answer 3

Milankovitch cycle - eccentricity, axial tilt/obliquity, wobble/precession

Question 4

what is wobble/precession?

Answer 4

The earth wobbles on its axis so the sun varies radiation leading to varied summer and winter temps. It happens on a 21,000 year timescale.

Question 5

What is axial tilt/obliquity?

Answer 5

When the earths axis tilts from 21.8 to 24.4 degrees which impacts the intensity of light at poles, cooler summers and warmer winters. This happens on a 41,000 year timescale.

Question 6

What is eccentricity?

Answer 6

When the orbit changes from elliptical to circular so there is more radiation from the sun at certain points. This happens on a 100,000 year timescale.

Question 7

What are short-term causes for climate change?

Answer 7

Solar forcing and volcanic causes

Question 8

What is volcanic causes?

Answer 8

Highly explosive volcanoes eject large amounts of ash and water vapour into the atmosphere and block out sunlight.

Question 9

What is solar forcing?

Answer 9

Energy emitted by the sun varies due to sunspots, cycling every 11 years. 1645-1715 little ice age, 850-1250 medievel warm period

Question 10

What is a feedback mechanism?

Answer 10

Climatic feedbacks can either amplify a small change (positive feedback) or diminish the change and make it smaller (negative feedback).

Question 11

Factors of a warm based glacier

Answer 11

-occur at high altitudes outside polar regions
-temps on the surface fluctuate to above and below freezing
-liquid at the bottom causes them to continously melt

Question 12

Factors of a cold based glacier

Answer 12

-average temp below 0
-limited surace melt during polar summer
-basal layer has far less debris

Question 13

What is aspect?

Answer 13

It determines the amount of snow that settles. Relief and aspect in mountainous areas combine to affecet where cirques form.

Question 14

Unconstrait glaciers

Answer 14

Tend to be larger forms such as ice caps and sheets, thick and extensive and often submerge the landscape.

Question 15

Constraint glaciers

Answer 15

Those that have a physical limit such as valley glaciers where the landscapeconstraints where they are and tend to only drain one way.