The Role of Fresh Water and Salt Fluxes in Southern Ocean Deep-Ocean Warming

Abstract:

The Southern Ocean plays a major role in global ocean circulation, a system of surface and deep currents, linking all oceans and one of the fundamental determinants of the planet’s climate. Because the Southern Ocean around Antarctica is the only location where the ocean can circulate freely all the way around the globe without continental barriers, it's a huge part of the ocean cycle. Despite this recent increase in our understanding of the Southern Ocean system, there is still uncertainty in the fluxes and transport of fresh and salt water within this region. Difficulties arise when studying the fluxes and transports within the Southern Ocean due to lack of research focusing on the following: the sources of freshwater inputs into the Southern Ocean system, the circulation of the ocean, and the vertical stratification. Satellite-derived salinity from the Aquarius salinity mission (September, 2011-present) and Simple Ocean Data Assimilation (SODA) Reanalysis (1950-2010) are used to estimate freshwater and salt fluxes. Our results indicate that recent changes in freshwater and salt fluxes are a major component of the deep-ocean warming in the Southern Ocean. In particular, the role of changes in these fluxes in causing surface cooling and increasing deep oceanic storage of heat in the Southern Ocean is investigated.