Lecture 15 - A World of Changing Environments

Question 1

How does Altitude affect Precipitation for the formation of Glaciers?

Answer 1

-High elevation = more precipitation
-Colder air up mountains means less moisture
-Therefore it is released at altitude where it is likely to precipitate as snow

Question 2

What is Firnification?

Answer 2

-Snow turning to ice as it is progressively compressed under the weight of layers of snow
-Air passages sealed at a density of 830kg/m3 which transforms the snow into ice

Question 3

What is Ablation and what are some Examples?

Answer 3

-Ablation = loss of mass from the glacier
-Sublimation (lost as gas)
-Calving (solid, ice mass terminates in a water body)
-Melting (liquid)

Question 4

What are the Ideal conditions for Glacier Formation?

Answer 4

-Precipitation bias to snow
-Cold/mild winters/ temp <0 degrees
-High humidity
-Low temperatures
-Cool summers
-Snowpack maintained (positive mass balance)

Question 5

Difference between Continental and Maritime Glaciers

Answer 5

-Low accumulation and ablation on continents, opposite on maritime
-Slow and fast response to accumulation change respectively

Question 6

Define Ice Sheet

Answer 6

-Massive amounts of ice covering continents
-Comprise 95% of all glacial ice
-Greater than 50,000km2
-Largely topographically unconstrained except when flowing into oceans

Question 7

Define Ice Shelf

Answer 7

-Floating sections of the ice sheets
-Area is still included as part of the ice sheet

Question 8

Define Alpine/ Valley Glacier

Answer 8

-Formed in and restricted to mountainous areas
-Comprise a small portion of Earth’s total glacier ice
-Largely topographically constrained except where flowing out of a valley to produce a piedmont glacier