L3 - Glacer Mass Balance Flashcards
What does accumulation at high elevations do?
Add Mass
What does ablation at low elevations do?
Remove Mass
What is Mass Balance?
The difference between mass gains and mass losses (it can be +ve or -ve)
What 3 things is glacier mass balance a function of?
- Climate
- Local Topography
- Glacier Hypsometry
What is Hypsometry?
Area to Elevation Ratio
Give 4 processes of accumulation
- Snowfall
- Wind Drift
- Avalanching
- Meltwater Freezing (Rimming & Superimposed Ice)
Give 4 processes of ablation
- Surface and/or basal melting
- Sublimation
- Avalanching
- Calving (Wet or Dry)
What is Sublimation?
The move from a Solid to a Gas
What is Calving?
The process by which ice breaks off a glacier terminus
What are processes of accumulation and ablation important for?
Budgets
What are the 4 zones within the accumulation zone (in order - starting furthest from the ELA)?
- Dry Snow Zone
- Percolation Zone
- Wet Snow Zone
- Superimposed Ice Zone
In which accumulation zone do you get firn?
The Percolation Zone
What is the ELA?
The Equilibrium Line Altitude - the point where ablation = accumulation
What causes the ELA to vary?
Glacier type, morphology, location, time of year and hypsometry
Why is the ELA an indicator of glacier health?
The more downhill it is, the more accumulation there is, hence a healthy glacier