Comparison of warming trends predicted over the next century around Antarctica from two coupled models

This paper investigates the climate change in two atmosphere-ice-ocean coupled climate models - the UKMO and the CSIRO - in the Antarctic region over the next century. The objectives were to see if an enhanced level of greenhouse-gas forcing results in a surface temperature signal above background variability, and to see if this pattern of change resembles the change seen to date in Antarctica, especially the warming around the Peninsula. The models show that although reduced sea-ice compactness is responsible for regions of enhanced air-temperature anomalies, these ice-compactness anomalies are determined by different mechanisms in the respective models. The pattern of warming in both models does not match the differential rates of warming seen in the observations of temperature change over the Antarctic continent in the last few decades. Also the level of background ocean variability in the Drake Passage and Weddell Sea region hampers the clear definition of a signal over the Antarctic Peninsula in the coupled models. Although no winter enhancement in warming over the Peninsula region is found, an autumn anomaly is seen in one of the models. The mechanism for this feature is documented, and an explanation of why it does not persist throughout the winter season is presented.

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