Summary
The parameterization of gravity waves in the NCAR Whole Atmosphere Community Climate Model (WACCM) includes orographic, convective, and frontal sources. Even with these, the model simulates temperatures in the Antarctic lower stratosphere during winter and spring that are much lower than observed. Recent simulations have shown that polar stratospheric temperatures are much improved by including another set of gravity waves that have horizontal wavelengths in the inertia-gravity range (several hundred km). The impact of orographic waves has also been reassessed after comparisons with wave observations. Improvements include a more realistic seasonal development of the ozone hole and somewhat better timing for the winter to summer transition in the zonal winds and Brewer-Dobson Circulation. We will demonstrate the role of these additional waves in shaping the middle atmosphere climatology and will show comparisons with observations of wave characteristics that constrain the parameterization.
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