observations of melt pond evolution and sea ice albedo

Observations of Melt Pond Evolution and

Sea Ice Albedo

Chris Polashenski1 and Don Perovich2

1 Thayer School of Engineering, Dartmouth College Hanover NH, 2 US Army Corps of Engineers CRREL Laboratory Hanover NH

Key Questions:

•  What is the albedo of a melt pond? •  How much area is covered by ponds?

6/4/2008

6/6/2008

6/7/2008

6/8/2008

6/9/2008

Channel

6/12/2008

6/14/2008

6/15/2008

6/17/2008

Drainage Flooding Growth

Date 2009

No Drainage

Ponds drain through

macroscopic holes

-Flow stops in holes -Ice permeable

-Ponds at sea level -Growth dictated by

ice freeboard

Spatial Coverage Detail, Scene Repeatability

MY Ice

Mixed Ice

FY Ice

MY Ice

FY Ice

Pond Volume Parameterization CCSM CICE 4.0

New pond volume = old pond volume + 10% of the new melt water

CICE 4.0 Documentation

Pond fraction is related to pond depth by a factor of 0.8

Comparing CICE 4.0 to Observations

CICE 4.0 Predicted Pond Fraction Observed Pond Fraction

Comparing CICE 4.0 to Observations

CICE 4.0 Predicted Pond Fraction Observed Pond Fraction

Difference - 60 MJ/m^2 Enough to melt ~20cm Ice

Summary •  First year ice is becoming more prevalent in the Arctic •  FY ponds behave is quite differently from MY ponds •  Early season ponds on FYI form above hydrostatic

equilibrium and have large coverage •  Duration of this flooding could significantly effect melt. •  Understanding the mechanisms which control meltwater

drainage is crucial for modeling FY ponds

•  If you have unpublished melt pond coverage data, I’d like to collaborate with you!

Thank You Collaborators

Don Perovich, Zoe Courville, Dave Finnegan

Barrow Arctic Science Consortium

NSF Grant No. ARC-0454900