SO-CHIC Gülk, B., Roquet, F., Naveira Garabato, A. C., Narayanan, A., Rousset, C., Madec, G. (2023): Variability and remote controls of the warm-water halo and Taylor cap at Maud rise, XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) (Berlin 2023).

June 30, 2023 Birte Gülk; Fabien Roquet; Alberto C. Naveira Garabato; Aditya Narayanan; Clément Rousset; Gurvan Madec

The region of Maud Rise, a seamount in the Weddell Sea, is known for the occurrence of irregular polynya openings during the winter months. Hydrographic observations have shown the presence of a warmer water mass below the mixed layer along the seamount’s flanks, commonly termed the warm-water Halo, surrounding a colder region above the rise, the Taylor Cap. A combination of observational data sets, an eddy-permitting reanalysis product and a regional high-resolution configuration allows to investigate the properties of these features and shows a strong interannual variability. A warming of deep waters is observed in the Taylor Cap during the years preceding the opening of the Polynya in 2016 and 2017, starting in 2011. By analyzing regional simulations, we are able to demonstrate that most of the observed variability in the warm-water Halo is forced remotely by advection of Weddell Gyre deep waters in the region surrounding Maud Rise. Deep water anomalies found in the Halo are retroflected along the inner flank of the Halo and from there transported into the Taylor Cap by eddies within the next six months. In addition to the preconditioning of the ocean preceding the Polynya opening, we investigate the role of thermobaricity in the region of Maud Rise in the period before the Polynya opening by implementing the eddy-diffusivity mass-flux parameterization in 1D simulations and the regional configuration.

Publication DOI: https://doi.org/10.57757/IUGG23-2594