The Flow of Dense Water Plumes in the Western Weddell Sea Simulated with the Finite Element Ocean Model (FEOM) - Towards an Interdisciplinary Approach in Earth System Science - page 118

proposed for this region (e.g. Garc flows along the

northern rim of Powell Basin, leaving the Weddell Sea at the western margin of
Philip Passage.
In L2, part of the plume

í a et al. 2002 ). The other branch fl

flows down the slope and is carried by the Weddell
Gyre, while the water that remains on shelf

fl

flows north with smaller velocities
(Fig. 1 ). The portion transported by the gyre enters Powell Basin,

fl

ows around
South Orkney Island and leaves the Weddell Sea through the South Orkney
Passage, with some leakage of dense water through Philip Passage. The waters
remaining on the continental shelf follow the same path as described in L1.
In simulation S2 the spreading paths are similar to L2, but the dilution by the
surrounding ambient takes a longer time (distance) and the plume water reaches
greater depths than in the other runs. When lighter water is prescribed (S1), the
northward

fl

flow is restricted to the continental shelf and the upper part of the slope,
and the dilution below the shelf break is higher. When the traced water gets closer
to the tip of the AP a behavior analogous to the

fl

first 90 days of L1 is observed, but
the simulation period ends before the southwestward fl flow into BS can occur.

4 Summary and Conclusions

Our experiments have shown that dense water found close to the tip of the Ant-
arctica Peninsula fl flows mainly into Brans eld Strait, while if it is located further

south, it can flow down the slope and contribute to the WSDW that might be

converted into AABW. The importance of the waters from the northwestern
Weddell Sea for the fringing basins is already known, but we showed that the
location where the plume starts de

fl

nes whether it will fl flow into Brans eld Strait or

into the Scotia Sea.
This result support the idea that the freshening of the deep waters from BS
(Garcia and Mata 2005 ) is associated with the freshening observed on the north-
western Weddell Sea (Hellmer et al. 2011 ). Further investigation of this subject will
be carried out using the Finite Element Sea Ice-Ocean Model (FESOM) (Wang
et al. 2013 ), a model that simulate sea-ice formation and the interaction with the
fringing ice shelf, both crucial for the dense water production.
Another crucial factor for the spreading of the LIS plume is its initial density.
Lighter water mixes faster with the ambient waters and does not in

uence the
WSDW while denser water sinks to greater depth. Due to the lack of data, the
variability of the plume is not known. Modelling attempts will be made to illu-
minate this issue, but in situ measurements are indispensable for understanding this
region, its in

fl

fl uence on the fringing basins, and its importance for the World Ocean.

Acknowledgments We would like thank Mauricio Mata and Oliver Huhn (reviewers) for their
comments to improve this manuscript and the suggestions for the future work. The rst author was
supported by CNPq grant 290034/2011-6.