Wall profiles

 

Leads are dark and absorb over 90% of the incident sunlight. The most important questions to be addressed are: how much of the solar energy entering a lead is lost to lateral melting, and how much goes down into the mixed layer where most of it will ultimately be used to thin the ice? We investigated this at Seattle where we measured lateral ablation and ice edge profiles at 2-3 day intervals. This site included a line of wire thickness gauges oriented perpendicular to the floe edge that can estimate heat lost to the underside of the ice by lead water flowing under the floe. Wave action in leads results in enhanced edge ablation at the water line necessitating measurements of the ice wall profile at the floe edge. Routine measurements at these sites included: ice wall profiles, lateral and bottom ablation rates, lead albedo, surface temperature, lead width and amount of brash in the water.

 

Measuring wall profiles at Seattle, July 1997

Ice edge undercut July 1997. Undercut is more than 1 m.

 

Time series of wall profiles from the ice edge at Seattle.

 

 
 
                                          

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