Impact of sea-ice formation on the properties of Antarctic Bottom Water

• Main Authors: Goosse, Hugues, Campin, Jean- Michel, Fichefet, Thierry, Deleersnijder, Eric
• Other Authors: UCL - SST/ELI/ELIC - Earth & Climate
• Format: Article in Journal/Newspaper
• Language: English
• Published: International Glaciological Society 1997
• Subjects: bottom water; ocean-ice system; salinity; salt advection; sea ice; 1443; Antarctic; The Antarctic; Annals of Glaciology; Antarc*; NADW; North Atlantic Deep Water; North Atlantic; Sea ice
• Online Access: http://hdl.handle.net/2078.1/129426

It is generally accepted that fresh-water fluxes due to ice accretion or melting profoundly influence the formation of Antarctic bottom water (AABW). This is investigated by means of a global, three-dimensional ice-ocean model. Two model runs were conducted. At the high southern latitudes, the control experiment exhibits positive (i.e. towards the ocean) fresh-water fluxes over the deep ocean, and large negative fluxes over the Antarctic continental shelf, because of the intense ice-production taking place in this region. The salinity of shelf water can increase in such a way that deep-water formation is facilitated. The simulated net fresh-water flux over the shelf has an annual mean value of -1 m a-1. This flux induces a transport of salt to bottom waters, which corresponds to an increase of their salinity estimated to be around 0.05 psu. In the second model run, the fresh-water fluxes due to ice melting or freezing are neglected, leading to a rearrangement of the water masses. In particular, the AABW-formation rate decreases, which allows the influence of North Atlantic deep water (NADW) to increase. As NADW is warmer and saltier than AABW, the bottom-water salinity and temperature become higher.