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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• If you have unpublished melt pond coverage data, I’d like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

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