Transoceanic infragravity waves impacting Antarctic ice shelves
Peter D. Bromirski (Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, U.S.A.), Olga V. Sergienko (AOS Program, Princeton University, Princeton, NJ, U.S.A.) and Douglas R. MacAyeal (Department of the Geophysical Sciences, University of Chicago, Chicago, IL, U.S.A.)
Abstract
Long-period oceanic infragravity (IG) waves (ca. [250, 50] s period) are generated along continental coastlines by nonlinear wave interactions of storm-forced shoreward propagating swell. Seismic observations on the Ross Ice Shelf show that free IG waves generated along the Pacific coast of North America propagate transoceanically to Antarctica, where they induce a much higher amplitude shelf response than ocean swell (ca. [30, 12] s period). Additionally, unlike ocean swell, IG waves are not significantly damped by sea ice, and thus impact the ice shelf throughout the year. The response of the Ross Ice Shelf to IG-wave induced flexural stresses is more than 60 dB greater than concurrent ground motions measured at nearby Scott Base. This strong coupling suggests that IG-wave forcing may produce ice-shelf fractures that enable abrupt disintegration of ice shelves that are also affected by strong surface melting. Bolstering this hypothesis, each of the 2008 breakup events of the Wilkins Ice Shelf coincides with wave-model-estimated arrival of IG-wave energy from the Patagonian coast.
Received 23 October 2009; accepted 14 December 2009; published 29 January 2010.
Citation: . (2010). Transoceanic infragravity waves impacting Antarctic ice shelves, Geophys. Res. Lett., 37, L02502; doi: 10.1029/2009GL041488.
Link: http://www.agu.org/pubs/crossref/2010/2009GL041488.shtml
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