Why has the Antarctic Peninsula stopped warming?

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• John Turner (British Antarctic Survey)
• Tuesday 12 January 2016, 14:00-15:00
• room 307, British Antarctic Survey, High Cross, Cambridge, CB3 0ET.

If you have a question about this talk, please contact James Pope.

Over the second half of the Twentieth Century the stations on the Antarctic Peninsula experienced some of the largest increases in surface air temperature seen in the Southern Hemisphere. However, the observations from six stations with long records show that since the late 1990s the warming has ceased or switched to a significant cooling. I will discuss the factors that influence surface temperatures across the Peninsula, and then focus on the differences in atmospheric and oceanic conditions between the warming and cooling periods. From 1979 to the late 1990s the Southern Annular Mode (SAM) became more positive, with strengthening westerly winds over the Southern Ocean, a deepening Amundsen Sea Low and decreasing sea ice around the Peninsula. However, over the last 16 the SAM had experienced no overall trend, while the higher frequency of La Nina-like lower sea surface temperatures across the tropical Pacific has contributed to a strengthening of the Polar Front Jet, giving more cyclonic activity in the Drake Passage and a higher frequency of easterly winds over the northern Weddell Sea that has increased the amount of sea ice around the northern part of the Peninsula. I will discuss how the recent temperature trends relate to the palaeoclimate records from the Peninsula and consider the degree to which we can predict the climate of the Peninsula over the coming decades.

This talk is part of the British Antarctic Survey series.

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• room 307, British Antarctic Survey, High Cross, Cambridge, CB3 0ET

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