Behrens, Lisa Katharina (2012) Das arktische Meereis in Klimamodellen - Variabilitäten und anthropogener Klimawandel. (Diploma thesis), Christian-Albrechts-Universität, Kiel, Germany, 167 pp.

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Abstract

Changes due to global warming are particularly obvious in the Arctic. Anisimov et al. (2007, Chapter 15.2.1) show, that the warming in the Arctic is twice as strong as the mean global warming. Hence, changes in arctic sea ice will be regarded in this diploma thesis. Therefore, the CMIP3-Models for the A1B-Scenario are used. Changes are studied for the entire Arctic as well as for different regions of the Arctic. In all regions the models show a reduction in the sea ice extent, the sea ice thickness and the sea ice volume. Furthermore, this reduction is visible in the amplitude of the seasonal cycle. The phase of the seasonal cycle shows a shift of the maximum of the sea ice extent. These maximum extents are later in the year. However, this effect is not visible for the other two parameters. The sea ice extent shows a sensitivity to global warming in the whole arctic as well as in the different regions. The sensitivity varies for the annual mean and the seasonal means of summer and winter. The models show a similar sensitivity in the winter mean in the whole arctic. However, for regions like the Barents Sea the models simulate different sensitivities. The interannual variability of the sea ice extent is changed due to a reduction in the sea ice extent. Without the anthropogenic warming the variability of the sea ice extent in March exceeds the variability of September. In contrast, at the end of the 21st century the sea ice extent in Sepember exceeds the variability in March. However, no changes in the multi decadal variability are visible. Furthermore, three of 19 models exhibit a relationship between the reduction of the sea ice concentration and cold winters over the Eurasian continent. For a high sea ice concentration in the Barents Sea, a positive temperature and a negative pressure anomaly are present over the Eurasien continent. With a reduction of the sea ice concentration, there is a negative temperature and a positive pressure anomaly. This shifts back to a positive temperature and a negative pressure anomaly for low sea ice concentration. Thus, a reduction of sea ice concentration could influence the atmospheric circulation.

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