Terra Nova Bay Polynya dynamics, surface heat fluxes and their impact on thermohaline variability of the water column

• Main Authors: Fusco, G., Aulicino, G., Capozzi, V., Cotroneo, Y., Esposito, M., Sansiviero, M., Budillon, G.
• Format: Conference Object
• Language: English
• Published: 2023
• Subjects: Antarctic; Austral; Ross Sea; Terra Nova Bay; The Antarctic; Antarc*; Sea ice
• Online Access: https://gfzpublic.gfz-potsdam.de/pubman/item/item_5017912

Polynyas, persistent sea-ice-free areas during the austral winter, act like "windows" that expose the relatively warm ocean to the colder atmosphere. One of these polynyas is recurrently detected in the coastal area of Terra Nova Bay (TNB) in the Ross Sea. The TNB polynya is important in the modification of the thermohaline structure of the whole Ross Sea. Brine release during sea ice formation increases the salinity of the subsurface water, resulting in the formation of High Salinity Shelf Water (HSSW), that is the prime ingredient in the formation of the Antarctic Bottom Water. The aim of this study is to investigate the processes that occur in the TNB polynya and the role of the air-sea interactions in the determination of its opening, activity and on the HSSW production. First, we analyzed the role of the katabatic winds using meteorological data by the AWSs and ECMWF data, since 1994. In the second step the open water areas from 2005 and 2021, detected by the MODIS data, were used to estimate the opening and the activity of the polynya during the winter season. Then, we estimated the surface heat budget via empirical formulae in the investigated period. Assuming that ice production rate depends on the net heat flux and on the polynya extension, it is possible to calculate the total production of salt released during sea ice formation and HSSW volume. Finally, a comparison between the estimated HSSW production and the salinity observed within the TNB water column is carried out.