glacial systems and processes

Question 1

what are the 2 processes in a glacial system

Answer 1

-accumulation - this is the addition of mass to the glacier, precipitation - usually snow

-ablation - this is the loss of mss from a glacier. this includes meltwater and avalanches

Question 2

what is the glacial budget

what is the difference between a positive glacial budget and a negative glacial budget

why do glacial budgets fluctuate annually

Answer 2

-the glacial budget refers to the mass balance of a glacier, i.e the difference between the accumulation and ablation

-a positive glacial budget shows accumulation exceeding ablation, so the glacier is advancing

-a negative glacial budget shows ablation exceeding accumulation, so the glacier is retreating

-glacial budgets fluctuate annually due to seasonal variation
-in the summer months, there is more ablation
-in the winter months there is more accumulation

Question 3

what types of systems are glaciers, what does ths mean

what are inputs into the glacial system

what are outputs in the glacial system

what are the stores

what are the flows

what is meant by dynamic equilibrium

Answer 3

-glaciers are natural systems, this means that there are specific interactions in their development and sustaining that allow glaciers to work

inputs:
-precipitation - snow/hail
-eroded debris

outputs:
-meltwater
-ablation processes (e.g evaporation/avalanches)
-calving

stores:
-subglacial
-englacial
-supraglacial

flows:
-compressional fow
-extensional flow

-dynamic equilibrium refers to a state of balance, when accumulation=ablation

Question 4

what is a positive feedback loop
give a positive feedback loop in glaciers (increasing temp)

what is negative feedback
give a negative feedback loop in glaciers (temperature rise)

Answer 4

-A positive feedback loop occurs when a process amplifies the initial change, leading to further intensification of that change
-temperatures increase -> permafrost melts -> co2 is released -> increased greenhouse affect -> further increasing temperatures

-A negative feedback loop occurs when a process counteracts the initial change, preventing further intensification.
-temperatures rise -> permafrost melts -> more plants to take in co2 -> greenhouse effect lessens -> temperatures fall

Question 5

Historical periods of glacial advance and retreat:

what determines whether glaciers globally will advance or retreat
currently are glaciers advancing or retreating, why is this

since the last glacial maximum 21,000 years ago, have global temperatures been increasing or decreasing

however, there have been recent smaller global coolings, give an example of one, how did this affect glaciers in the alps

Answer 5

-whether glaciers will advance or retreat is dependent on the period, in a glacial period they will advance and in a interglacial period they will retreat
-currently glaciers are retreating this is due to the world being in an interglacial period

-since the last glacial maximum, global temperatures have been increasing

-an example of a recent smaller global cooling is the ‘Little ice age’ that occured between 1300 and 1870, this is the most significant.
-this affected glaciers in the alps as it lead to large amount of glacial advance.