Modeling winter circulation under landfast ice : the interaction of winds with landfast ice
MetadataShow full item record
Idealized models and a simple vertically averaged vorticity equation illustrate the effects of an upwelling favorable wind and a spatially variable landfast ice cover on the circulation beneath landfast ice. For the case of no along-shore variations in ice, upwelling favorable winds seaward of the ice edge result in vortex squashing beneath the landfast ice leading to (1) large decreases in coastal and ice edge sea levels, (2) cross-shore sea level slopes and weak (<~.05 m s−1) under-ice currents flowing upwind, (3) strong downwind ice edge jets, and (4) offshore transport in the under-ice and bottom boundary layers of the landfast ice zone. The upwind under-ice current accelerates quickly within 2–4 days and then slows as cross-shore transport gradually decreases the cross-shore sea level slope. Near the ice edge, bottom boundary layer convergence produces ice edge upwelling. Cross-ice edge exchanges occur in the surface and above the bottom boundary layer and reduce the under-ice shelf volume by 15% in 10 days. Under-ice along-shore pressure gradients established by along- and cross-shore variations in ice width and/or under-ice friction alter this basic circulation pattern. For a landfast ice zone of finite width and length, upwelling-favorable winds blowing seaward of and transverse to the ice boundaries induce downwind flow beneath the ice and generate vorticity waves that propagate along-shore in the Kelvin wave direction. Our results imply that landfast ice dynamics, not included explicitly herein, can effectively convert the long-wavelength forcing of the wind into shorter-scale ocean motions beneath the landfast ice.
Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 117 (2012): C04006, doi:10.1029/2011JC007649.
Showing items related by title, author, creator and subject.
Spall, Michael A. (American Meteorological Society, 2015-11)The response of a convective ocean basin to variations in atmospheric temperature is explored using numerical models and theory. The results indicate that the general behavior depends strongly on the frequency at which the ...
The surface-forced overturning of the North Atlantic : estimates from modern era atmospheric reanalysis datasets Grist, Jeremy P.; Josey, Simon A.; Marsh, Robert; Kwon, Young-Oh; Bingham, Rory J.; Blaker, Adam T. (American Meteorological Society, 2014-05-15)Estimates of the recent mean and time varying water mass transformation rates associated with North Atlantic surface-forced overturning are presented. The estimates are derived from heat and freshwater surface fluxes and ...
Impact of surface forcing on Southern Hemisphere atmospheric blocking in the Australia–New Zealand sector Ummenhofer, Caroline C.; McIntosh, Peter C.; Pook, Michael J.; Risbey, James S. (American Meteorological Society, 2013-11-01)Characteristics of atmospheric blocking in the Southern Hemisphere (SH) are explored in atmospheric general circulation model (AGCM) simulations with the Community Atmosphere Model, version 3, with a particular focus on ...