3.1.4.3 Systems and Processes Flashcards
What’s a glacier
Mass of ice moving downhill due to gravity
What’s a valley glacier
Glacier that fills valleys
Can be several km long
What’s a Corrie glacier
Smaller glacier found in a bowl shaped hallow high up in mountains
What are ice sheets
E.g
Domes of ice covering huge areas of land
E.g the Antarctic ice sheet
What’s the snow line
Point above which snow and ice cover the ground throughout the year
The snow and ice has survived the summer melting
What 2 things decrease as latitude increases
Snow line
Altitude
What 2 things happen when latitude decreases (closer to equator)
Snow line and altitude increase
How much snow can form at lower altitudes
Why
Less snow
Climate is warmer as air is more dense
Why is snow line higher nearer to the equator
The altitudes are higher so climates are colder so the snow line is higher as air is less dense so can’t retain much heat
So snow can form easier and less will melt
What’s aspect
Direction in which a slope faces
What’s the snowline on south facing slopes like
Why
Lower
It’s warmer
What’s the snowline like on north facing slopes
Why
Higher
They receive less sunlight so are cooler and snow can form easier with less melting
What’s the glacial budget
Balance between outputs and inputs of a glacial system
What’s the process of a glacier gaining mass
How does it do this
E.g
Accumulation
Due to inputs
E.g precipitation
What’s the process of a glacier losing mass
How does it do this
E.g
Ablation
Due to outputs
E.g meltwater
When does a glacier have a positive budget/net balance
How does the glacier move
If inputs exceed outputs (more accumulation)
Advances
When does a glacier have a negative budget/net balance
How does the glacier move
When outputs exceed inputs
Retreats
What is more likely to happen in winter
Inputs usually exceed outputs near the head of the glacier (more accumulation)
What is more likely to happen in summer and at lower altitudes
Outputs will exceed inputs (ablation)
What are most remaining glaciers doing today
Retreating
What’s a glaciers steady state known as
Dynamic equilibrium
2 historical periods to do with glacial advancement and retreat
The little ice age
Medieval warming period
When did the little ice age occur
1300-1850
2things that happened in the little ice age
Mountain glaciers expanded at several locations (alps, New Zealand, the southern andes)
Mean annual temperatures declined by 0.6*c across northern hemisphere
When was the medieval warming period
After the little ice age
Began in late 19th century + early 20th centuries
2 things the Hubbard glacier did from 1895-2001
Snout widened by 1 mile
Advanced further south-west
3 things the Mer de Glacé, France did
Retreated in north-east direction
Snout width decreased
More narrow now
Why is ablation happening at a much greater rate than accumulation
Enhanced greenhouse effect
Volcanic dust
Why is melting of ice sheets and glaciers an issue of world-wide concern
Animals e.g Arctic foxes , plants and humans are losing homes and habitats
Global land mass decreasing and sea volume is increasing
Dangerous cycle as sun continues to warm earth as ice disappears as ground is darker
Flooding of low-lying areas e.g London
What can ice do to sunlight
Reflect it away
