the opportunity to sample the variability of the
Southern Ocean on broad spatial scales for the first
time. The floats complement, but do not replace, the
high-density repeat sampling along fixed cruise
tracks required for transport estimates. Direct,
coherent and sustained in-situ measurements of
absolute velocity on large spatial scales, as required
to improve our understanding of the barotropic
flow, remain beyond our present technological
capacity. However, the combination of a highly
accurate and well-resolved geoid from planned satellite gravity missions and satellite altimetery will provide an unprecedented opportunity to resolve the
absolute flow of individual jets in the ACC, and
make possible quantitative studies of eddy–mean
flow interactions in the Southern Ocean. The Southern Ocean also remains a great challenge for ocean
models, which suffer their greatest difficulties where
strong currents and eddies interact with bottom
topography, a process central to the dynamics of the
ACC. While significant progress been made in the
theory, observation and modelling of the Southern
Ocean, we still do not have a realistic theoretical
picture of the dynamical processes that regulate the
response of the ACC to wind stress and thermohaline forcing. Only with such a picture will it be possible to place the WOCE observations into their
proper context and determine their limitations. The
challenge is to use and extend the WOCE data and
models to help build that picture.
Acknowledgements
We thank Trevor McDougall, Peter Baines, the
editors, and two anonymous reviewers for their
comments on an earlier draft. We also thank
Louise Bell and Jennifer Moss for preparing several figures. This work is supported in part by
Environment Australia through the CSIRO Climate Change Research Program. Contribution
No. 1628 from the Alfred-Wegener-Institute for
Polar and Marine Research.
SECTION 4 THE GLOBAL FLOW FIELD
302
Southern Ocean on broad spatial scales for the first
time. The floats complement, but do not replace, the
high-density repeat sampling along fixed cruise
tracks required for transport estimates. Direct,
coherent and sustained in-situ measurements of
absolute velocity on large spatial scales, as required
to improve our understanding of the barotropic
flow, remain beyond our present technological
capacity. However, the combination of a highly
accurate and well-resolved geoid from planned satellite gravity missions and satellite altimetery will provide an unprecedented opportunity to resolve the
absolute flow of individual jets in the ACC, and
make possible quantitative studies of eddy–mean
flow interactions in the Southern Ocean. The Southern Ocean also remains a great challenge for ocean
models, which suffer their greatest difficulties where
strong currents and eddies interact with bottom
topography, a process central to the dynamics of the
ACC. While significant progress been made in the
theory, observation and modelling of the Southern
Ocean, we still do not have a realistic theoretical
picture of the dynamical processes that regulate the
response of the ACC to wind stress and thermohaline forcing. Only with such a picture will it be possible to place the WOCE observations into their
proper context and determine their limitations. The
challenge is to use and extend the WOCE data and
models to help build that picture.
Acknowledgements
We thank Trevor McDougall, Peter Baines, the
editors, and two anonymous reviewers for their
comments on an earlier draft. We also thank
Louise Bell and Jennifer Moss for preparing several figures. This work is supported in part by
Environment Australia through the CSIRO Climate Change Research Program. Contribution
No. 1628 from the Alfred-Wegener-Institute for
Polar and Marine Research.
SECTION 4 THE GLOBAL FLOW FIELD
302