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.