Unit Affiliation: Ocean and Climate Physics, Lamont-Doherty Earth Observatory (LDEO)
Antarctic coastal polynyas are, at the same time, sea-ice free sites and sea-ice factories. They are open water surface locations where water mass transformation and densification occurs, and where direct atmospheric exchanges with the deep ocean circulation are established. Various models of the formation and persistence of these productive and diverse ocean ecosystems are hampered by the relative lack of in situ meteorological and physical oceanographic observations. This is especially so during the inhospitable conditions of their formation and activity during autumn to winter transition and the polar night. The Western Ross Sea, downstream from two of the largest coastal Antarctic polynyas, happens to be a region where there continues to be net sea-ice production, as indicated by satellite measurements of areal extent, duration and concentration. Characterization of the lower atmosphere properties, air-sea surface heat fluxes and corresponding ocean depth profiles of the Terra Nova Bay (TNB) polynya, is sought for a more detailed understanding of the role of polynyas in the production of latent-heat type sea ice and the formation, through sea ice brine rejection, of dense ocean bottom waters. This observational program will simultaneously identify mechanisms responsible for water mass modification within TNB and document aspects of dense shelf water formation within a large Antarctic polynya system. This study will characterize the water masses within a polyna over the course of an annual cycle using moorings yielding in-situ column and near-surface oceanic observation.