The linear and nonlinear time-mean energetics and spatial structure of storm tracks that develop on a basic state consisting of two zonally aligned jet streaks is examined using a two-layer quasigeostrophic model of the wintertime Northern Hemispheric flow. Emphasis is placed on examining separately and in combination the effects of jet streak separation and zonal variations in local stability on the storm tracks. It is shown that these background flow features play a significant role in the morphology and intensity of the storm tracks. This storm track responses are also modulated by the strength of the basic flow between the jets. By changing the spatial patterns of the time-mean physical processes that contribute to the growth and decay of eddies, the strength and location of the storm tracks are altered in ways that are not in complete agreement with predictions based on studies involving isolated baroclinic regions. We find that the low frequency response of the eddies as a function of jet separation differs in both spatial distribution and magnitude from the response of the higher frequency eddies, with bandpass eddy activity concentrated close to the jet exit region, and low frequency eddy activity further downstream.
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12th Conference on Atmospheric and Oceanic Fluid Dynamics