A modelling and remote sensing study of Antarctic icebergs.
This is the first large-scale modelling study of iceberg trajectories and melt rates
in the Southern Ocean. An iceberg model _ was seeded with climatological iceberg
calving rates based on a calculation of the net surface accumulation from each snow
catchment area on the Antarctic continent. In most areas modelled trajectories show
good agreement with observed patterns of iceberg motion, though discrepancies in
the Weddell Sea have highlighted problems in the ocean general circulation model
output used to force the iceberg model. The Coriolis force is found to be important
in keeping bergs entrained in the coastal current around Antarctica, and topographic
features are important in causing bergs to depart from the coastal regions.
The modelled geographic distribution of iceberg meltwater joining the ocean has
been calculated, and is found in many near coastal regions to be comparable in
magnitude to the excess of precipitation over evaporation (P-E).
A remote sensing study of icebergs has been carried out in two locations in the
Weddell Sea using SAR. This study has, for the first time, been able to calculate
iceberg fluxes from satellite. The southwestwards flux of icebergs within 20 km of
the coast at around 18°W, based on a one month period of observations, has been
calculated at 50 to 70 Gta-1 (1Gt = 1012kg). This is 4 to 5% of the total iceberg
discharge from Antarctica.
The question of Antarctic mass balance is considered through comparison of modelresults and observations. Although a conclusion is not reached here, plans are presented
for an iceberg observing programme and further model development which
could resolve the problem