1a. Glaciated landscapes can be viewed as open systems
Inputs
Processes
Outputs
Glacier mass balance
Kinetic energy from wind and moving glaciers
Glaciated landscapes store and transfer energy and material on time scales that can vary from a few days to millennia
Thermal energy from the heat of the Sun
Potential energy from the position of material on slopes; material from deposition, weathering and mass movement from slopes and ice from accumulated snowfall
Glacial and wind erosion from rock surfaces
Evaporation
Sublimation
Meltwater
Stores
Ice
Water
Debris accumulations
Flows
Movement of ice
Movement of water
Movement of debris downslope under gravity
System is under dynamic equilibrium and undergoes self regulation to restore equilibrium through negative feedback
Accumulation - Ablation ( in a glacier over a one year time period )
Positive = Glacier advances
Negative = Glacier retreats
Firn line/ equilibrium line the balance between accumulation and ablation
Ablation zone = Snout
Accumulation zone = Upper area
Seasonal variations occur so advance may still occur despite net budget being negative
Even when in a retreat, the ice in a glacier may move forwards across the firn line under gravity --> A retreating glacier appears to advance
Mass balance of a glacier is not constant