Mountain Glaciers

Mountain Glaciers

1. Sea Level Changes

   • 3.3mm/yr
     • 1.5 cryosphere
     • 1.1 thermal expansion
     • 0.6 land water
   • Glaciers + ice caps
     • 0.7mm/yr
     • ~200,000 glaciers
     • 0.5% land surface
       • 730,000km2
     • 0.41m SLE
   • GrIS
     • 0.65mm/yr
   • AIS
     • 0.15mm/yr

2. Glacier Mass gain/loss

   • accumulation - ablation = glacial budget
   • Equilibirum line altitued = accum and ablation equal
   • glacial flow from accum to ablation
   • increase ice mass
     • ^ accum, decrease ablation, decrease calving
     • vice versa for gain
   • observation methods
     • GRACE
     • remote areas
     • scale
     • repeatable
     • ease access

3. Methods for detecting change

   • glacier length
     • terminus position
       • global distribution
       • space/time sparse
       • satellite, photo, moraines
   • glacier area
     • outlines
       • satellite, photos, trim lines, moraines
   • glacier volume/mass
     • ice stakes
       • labour/time intensive
     • GRACE satellite
       • direct measure mass change
     • surface elevation change
       • converted mass change
         • ice/snow density
           • ice = ~900kg m-3
           • snow = ~600kg m-3
       • synthetic aperture radar interferometry
       • stereo imagery
       • Altimetry
   • volume > mass
     • height change * surface = VC
       • VC * density = mass change

4. Earth Observation

   • remote sensing
   • Electromagnetic Spectrum
     • wavelengths
   • active sensors
     • generate/use own signal
   • passive sensors
     • use natural emissions
   • ability of objects to reflect different wavelengths

5. Dynamics

   • temp
     • pole + elevation
   • precip
   • orography (relief)
   • snowline
     • snowfall match melting
   • surface energy balance
     • energy in vs energy out
       • for melting
   • glacier in balance
     • ice flow from accumulation = melting in ablation
   • Karakaroma anomaly
     • same location, different behaviour
     • himalaya = snow summer
       • karakaroma = snow winter
     • caused by Hadley Cell
       • move south in winter, colder winds blown over Karakaroma (west)
   • glacier thickness/mass continuity
     • is mass doesn't = 0, thickness change
     • increase length = more ice in ablation = more ablation
       • longer glacier melt more
   • Surging glaciers
     • internal variability, not climate
     • pressure water