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Interannual Variability in Antarctic Sea Ice Motion

Interannual Variability in Antarctic Sea Ice Motion
Research Topic:Interannual Variability in Antarctic Sea Ice Motion
type:Thesis
tutor:Kottmeier, Ch.
person in charge:Schmitt, Carolin
links:Full text (PDF)

The sea ice around Antarctica plays an important role for the climate of the polar regions and impacts the coupling between atmosphere and ocean by various  processes.
Within this thesis, the variability of sea ice motion is investigated on different timescales and relations to anomalies in the general atmospheric circulation of the Southern Hemisphere are established.
The long term timeseries of sea ice motion and its variance exhibit pronounced fluctuations and beyond it a strong regional decrease in certain areas. This velocity decline is found to be in agreement with the positive trend  of the “Southern Annular Mode” observed over the last decades. On the interannual scale, ice motion and its kinematic parameters are  also influenced by the alternating pattern of the  “Southern Oscillations”. This is most evident in the opposite behaviour of anomalies in the Pacific Sector and the areas to the east of the Antarctic Peninsula.
Further results prove that  anomalies in sea ice extent and atmospheric parameters coming along with the eastward propagating “Antarctic Circumpolar Wave” can  be  linked to ice motion and  its variance in the inner pack.
Moreover, the fluctuations according to the  interannual  atmospheric mass redistribution  that manifests in the “Southern Semiannual Oscillations”  are also found in the sea ice velocity field. This is explained by the direct relation between atmospheric pressure distribution and wind field, as well as by momentum transfer from wind forcing to the sea ice. The dynamic and thermodynamic contributions to ice margin displacement are investigated and consistently explained.