11.6 Modelling of gravity wave induced temperature fluctuations over the Antarctic Peninsula

Wednesday, 1 May 2013: 4:45 PM
South Room (Renaissance Seattle Hotel)
Andrew Orr, British Antarctic Survey, Cambridge, United Kingdom; and J. S. Hosking, H. K. Roscoe, L. Hoffmann, P. Braesicke, and L. Abraham

Recent studies have suggested that increased polar stratospheric clouds (PSCs) are responsible for the large warming which has occurred in the mid-troposphere in Antarctic winter. However, current climate models do not properly represent PSCs, partly due to their inability to resolve gravity wave induced stratospheric temperature fluctuations, which creates localised cooling that leads to increases in the formation of PSCs. Here, we investigate the representation of orographic gravity wave induced stratospheric temperature fluctuations by the UK Met Office Unified Model (MetUM) against satellite observations for a case study over the Antarctic Peninsula. At high-resolution the MetUM realistically simulates the magnitude, timing, and location of the temperature fluctuations. However, the climate model is unable to represent the structure and magnitude of the disturbances. This work is important to assess parametrization schemes.
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