Summary
Links between changes in the southern polar stratosphere and tropospheric climate have been identified in both modelling and observational studies, highlighting the importance of an accurate stratosphere in climate models. However, atmospheric global climate model simulations often produce a background temperature structure in the southern winter polar stratosphere that is biased: “the cold pole problem”. In the absence of radiative heating through much of this time, it is clearly dynamics that sets the thermal state of this part of the atmosphere through wave-driven meridional and vertical circulations. Hemispheric differences in the manifestation of this problem point to a different balance between large scale waves (which are naturally represented in models) and gravity waves whose scales are of the order of model grid sizes (and are not naturally represented). The horizontal scale of gravity waves is smaller than the grid cell size in almost all climate models and parameterization schemes are used to represent them. However, these schemes typically have source distributions that are defined, use gravity wave parameters that are poorly constrained, and so will not respond correctly to predicted changes in tropospheric processes. It is apparent that our ability to predict stratospheric responses to changing dynamics, and the consequences for our tropospheric climate, depends on the correct parameterization of gravity waves. This poster will describe efforts to improve gravity wave parameterization schemes using observational capabilities available at Davis station, Antarctica. Techniques for forming a gravity-wave climatology will be described along with initial results. Links to modelling efforts and the end goal of scheme improvements will also be discussed.
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