England, M.H., J.S. Godfrey, A.C. Hirst and M. Tomczak
J. Phys. Oceanogr., 23, 1553-1560, 1993.
KeyWords
Abstract
Antarctic Intermediate Water, ocean general circulation models,
global ocean models, Southern Ocean, water-masses.
Realistic representation of the low-salinity tongue of Antarctic
Intermediate
Water (AAIW) has been achieved in a coarse-resolution ocean general
circulation model. The authors find that this water mass is not
generated by
direct subduction of surface water near the polar front. Instead, the
renewal
process is concentrated in the southeast Pacific Ocean off southern
Chile.
The outflow of the East Australian Current progressively cools (by
heat loss
to the atmosphere) and freshens (by assimilation of polar water,
carried
north by the surface Ekman drift) during its slow movement across the
South
Pacific toward the AAIW formation zone. Further, deep, warm advection
near
Chile enables more convective overturn. resulting in very deep mixed
layers
from which AAIW is fed into the South Pacific and also into the
Malvinas
Current. Along with this isolated region of AAIW renewal, the model
relies on
alongisopycnal mixing of fresh surface water from the polar front to
capture
a realistic circumpolar tongue of low salinity water at 1000-m depth.