Responses of surface heat flux, sea ice and ocean dynamics in the Chukchi-Beaufort sea to storm passages during winter 2006/2007: A numerical study

Abstract

This study investigates storm impacts on sea ice, oceanic dynamics, and surface heat flux in the Chukchi-Beaufort Seas using a coupled ice-ocean model (CIOM). Two types of storms affect the study area: Arctic-born cyclones and north-moving Aleutian lows, which lead to strong westerly and easterly winds, respectively. Driven by 6-hourly forcing, the CIOM successfully reproduced the storm impacts. Simulated sea ice movements are comparable to the satellite observations. Storms usually result in fast-moving ice, which is faster than the speed of the surface water, and the gap between sea ice and surface water speed increases with wind speed. Storms can alter the pathways of the Pacific inflow water: with westerly winds, the Pacific inflow water goes no further than the latitude of Wrangel Island, while with easterly winds the Pacific inflow water can flow northward into the interior Arctic basin. Strong easterly winds associated with north-moving Aleutian lows reverse the Alaskan Coastal Current and the Bering Slope Current, and induce upwelling along the north Alaska coast. Westerly winds associated with Arctic-born cyclones act in an opposite way. During the storms, heat loss to the atmosphere is about twice that of normal conditions, which is mainly attributed to increases of the sensible and latent heat fluxes over the open water. Heat loss over ice was quite stable with some small fluctuations in response to the storms.