Sea-ice thickness measurement based on the dispersion of ice swell

© G.Redvers/Tara Expeditions

Tara Arctic

David MARSANA, Jérôme WEISS, Eric LAROSE et Jean-Philippe MÉTAXIAN

Acoustical Society of America, January 2012, p.80-91.

Abstract

The dispersion of flexural waves propagating in the Arctic sea ice cover is exploited in order to
locally measure the ice thickness. The observed dispersion, for waves filtered in the 4–20 s period
interval, at up to 4 broad-band seismometers deployed in Spring 2007 near the North Pole, is compared
to a parameterized model that accounts for a complex wavefield made of a superposition of
independent plane waves with different amplitudes and back-azimuth angles. The parameterization,
that includes finding the best modeled ice thickness, is performed by using the cross-correlation
functions between the seismometers. The ice thickness is estimated to 2:560:2 m for the 1 kmlarge
floe the seismic stations were deployed on, which is coherent with other, independent measurements
at this site. This study thus demonstrates the feasibility of using broad-band seismometers
deployed on the sea-ice in order to passively measure the ice thickness, without requiring active
sources nor human intervention.