A modelling study of the hydrographic structure of the Ross Sea

Abstract. Dense water formation around Antarctica is recognized as one of the most important processes to climate modulation, since that is where the linkage between the upper and lower limbs of Global Thermohaline Circulation takes place. Assessing whether these processes may be affected by rapid climate changes and all the related feedbacks may be crucial to fully understand the ocean heat transport and to provide future projections. Applying the Coordinated Ocean-Ice Reference (CORE) normal year forcing we have run a 100-yr simulation using Regional Ocean Model System (ROMS) with explicit sea-ice/ice-shelf thermodynamics. The normal year consists of single annual cycle of all the data that are representative of climatological conditions over decades and can be applied repeatedly for as many years of model integration as necessary. The experiment employed a circumpolar variable resolution (1/2° to 1/24°) grid reaching less than 5 km over the inner continental shelf. With Optimum Parameter Analysis (OMP) the main Ross Sea (RS) water masses are identified: Antarctic surface water (AASW), circumpolar deep water (CDW), shelf water (SW) and ice shelf water (ISW). Current configuration allows very realistic representation, where results compare extremely well to the observations.