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Observations of Melt Pond Evolution<br />
and<br />
Sea Ice Albedo<br />
Chris Polashenski 1 and Don Perovich 2<br />
1 Thayer School of Engineering, Dartmouth College Hanover NH,<br />
2 US Army Corps of Engineers CRREL Laboratory Hanover NH
Key Questions:<br />
• What is the albedo of a melt pond<br />
• How much area is covered by ponds
6/4/2008
6/6/2008
6/7/2008
6/8/2008
Channel<br />
6/9/2008
6/12/2008
6/14/2008
6/15/2008
6/17/2008
Flooding<br />
Drainage<br />
Growth<br />
Date 2009
No Drainage<br />
Ponds drain<br />
through<br />
macroscopic<br />
holes<br />
-Flow stops in holes<br />
-Ice permeable<br />
-Ponds at sea level<br />
-Growth dictated by<br />
ice freeboard
Detail, Scene Repeatability<br />
Spatial Coverage
FY Ice<br />
Mixed Ice<br />
MY Ice
FY Ice<br />
MY Ice
Pond Volume Parameterization<br />
CCSM CICE 4.0<br />
New pond volume = old pond volume + 10% of the new melt water<br />
Pond fraction is related to pond depth by a factor of 0.8<br />
CICE 4.0 Documentation
Comparing CICE 4.0 to<br />
Observations<br />
CICE 4.0 Predicted Pond Fraction<br />
Observed Pond Fraction
Comparing CICE 4.0 to<br />
Observations<br />
Difference - 60 MJ/m^2<br />
Enough to melt ~20cm Ice<br />
CICE 4.0 Predicted Pond Fraction<br />
Observed Pond Fraction
Summary<br />
• First year ice is becoming more prevalent in the Arctic<br />
• FY ponds behave is quite differently from MY ponds<br />
• Early season ponds on FYI form above hydrostatic<br />
equilibrium and have large coverage<br />
• Duration of this flooding could significantly effect melt.<br />
• Understanding the mechanisms which control meltwater<br />
drainage is crucial for modeling FY ponds<br />
• If you have unpublished melt pond coverage data, I’d like<br />
to collaborate with you!
Thank You<br />
Collaborators<br />
Don Perovich, Zoe Courville, Dave Finnegan<br />
Barrow Arctic Science Consortium<br />
NSF Grant No. ARC-0454900