Linking the Atmospheric Boundary Layer to the Amundsen Gulf Sea-Ice Cover: A Mesoscale to Synoptic-Scale Perspective from Winter to Summer 2008

The link between the sea-ice cover of the Amundsen Gulf and the overlying atmospheric boundary layer was explored on a weekly timestep from winter to summer 2008. The total sea-ice cover was around 97% (3% leads) from 7 January to 21 April. From 28 April to 12 May, the total sea-ice cover approached 100%. From May 19, the total sea-ice declined rapidly to its July minimum of 3%. During the winter, a turbulent internal boundary layer (IBL), attributed to the upward flux of sensible heat (mean = 46 W m⁻²), was present in most of the mean daily potential temperature profiles. The mean latent heat flux was 1.7 Wm⁻². A turbulent IBL was also present in most of the mean daily profiles for early spring. Surface fluxes were not estimated. During late spring and early summer, a stable IBL, attributed to the downward flux of sensible heat (mean = −19 W m⁻²), was present in most of the potential temperature profiles. Both downward and upward fluxes of latent heat occurred in this period (means = −3.3 and 1.1 W m⁻²). The sensible heat flux estimates are consistent with the results of others; however, the latent heat flux estimates may be too small due to condensation/deposition within the IBL. The unconsolidated nature of the pack ice in the Amundsen Gulf, and the low sea-surface temperatures following break-up, were critical factors controlling the presence and type of IBL.