cryosphere (frozen water)
DESCRIPTION
Cryosphere (Frozen water). The shape of ice crystals cause ice to be less dense than liquid water This causes Ice to float with about 9% of the ice volume above water (91% below). A.k.a. the Tip of the iceberg. Time scales relevant to the cryosphere. 87% of ice is in Antarctica - PowerPoint PPT PresentationTRANSCRIPT
Cryosphere(Frozen water)
The shape of ice crystals cause ice to be less dense than liquid water This causes Ice to float with about 9% of the ice volume above water (91% below). A.k.a. the Tip of the iceberg.
Time scales relevant to the cryosphere
87% of ice is in Antarctica10% Greenland2.5% ice shelves (mostly Antarctic)
If all Ice melted sea levels would go up by about 65 meters (213 ft)
Snow cover
Essential for water resources in the western US
Roughly 75% of the Western US fresh water supply comes from snow pack.
Dendrite: Common six sided ice crystal / snow flake.
January or February have most NH snow cover.
Aside from Antarctica the SH has very little snow cover.
IPCC 2007 Figure 4.2
IPCC 2013 data
River and lakes Spring thaw
Most rivers are thawing earlier and freezing later.
Alpine Glaciers
Milk Lake glacier 1988
Milk Lake 2009
Glaciers around the world are in retreat
Permafrost
Methane possibly released from permafrost?
Methane possibly released from permafrost?
Methane change Since 2005
Methane change Since 2005
Methane change Since 2005
Land Ice
From GraceSee http://www.aber.ac.uk/greenland/Massbalance.html and Gravity Recovery And Climate Experiment
Right: Mass change distribution (2002-2009) across the ice sheet as determined by GRACE observations.
Land Icehttp://www.skepticalscience.com/east-antarctica-is-now-losing-ice.html
Ablation: Melt, sublimation, loss from wind, loss from flow
Equilibrium line: Accumulation = Ablation
2010 was an exceptional year for Greenland’s ice cap. Melting started early and stretched later in the year than usual. Little snow fell to replenish the losses. By the end of the season, much of southern Greenland had set a new record, with melting that lasted 50 days longer than average.
350 Gt – 1 mm sea level riseBoth Antarctica and Greenland have been losing ice over the past 8 years.
Ice flow speed increase with distance above ground
Side view
Top view:
Ice flow increases with distance from valley walls.
Basal melt can provide a lubricant to increase total ice flow.
Ice flow increases with increasing tilt of the mountain
Air bubbles trapped in ice can reveal atmospheric composition in the past (up to about 600,000 yrs).
When accumulation is greater than ablation in a certain zone the ice sheet :a)Growsb)Shrinksc)Stays the same size
Sublimation or calving
When accumulation is greater than ablation in a certain zone the ice sheet :a)Growsb)Shrinksc)Stays the same size
Sublimation or calving
Sea Ice
What happens to the water level when the ice melts?
a. Overflowsb. Goes downc. Stays the same
Sea Ice
What happens to the water level when the ice melts?
a. Overflowsb. Goes downc. Stays the same
From: http://earthobservatory.nasa.gov/Features/WorldOfChange/sea_ice.php
The yellow outline on each image shows the median sea ice extent observed by satellite sensors in September and March from 1979 through 2000.
Sept 2011
From: http://earthobservatory.nasa.gov/Features/WorldOfChange/sea_ice_south.php
• Average September Arctic Sea ice decreased by about 40 % • From 1980 to 2010.• Sept 2012 had the lowest Arctic sea ice coverage since 1979.
• Average January Arctic Sea ice decreased by about 6% From 1980 to 2010.
http://nsidc.org/arcticseaicenews/2011/020211.html
• Average September (winter) Antarctic Sea ice increased by about 3 % • From 1980 to 2010.
