Tidal contribution to sea ice variability in the Ross Sea from AMSR-E satellite data and modeling

The northwestern Ross Sea is subject to large amplitude diurnal tidal currents that affect sea ice motion and concentration. We identify the variability in winter sea ice concentration using single swath data from the AMSR-E passive microwave sensor on the Aqua satellite. Ice concentration along the shelf break and continental slope varies from ~60% to 100% on tidal time scales (~daily and bimonthly). These results agree reasonably well with simulated sea ice in a fine resolution (5-km) 3D ocean circulation model coupled with a sea-ice sub-model. By comparing simulations with and without tidal forcing added to realistic atmospheric forcing, we identify the time-averaged contribution of tides to sea ice concentration and thickness in this region. We then use these models to estimate the net contribution of tide-forced changes in sea ice to the exchange of heat between the ocean and atmosphere.