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A substantial component of CMS research is related to improving the capabilities and simulation fidelity of WACCM. J. Richter has been analyzing in detail the momentum budget and the resolved wave spectra of the stratosphere and mesosphere in WACCM3. Such analyses are crucial to validating the processes that are driving the dynamical behavior in WACCM. The extra-tropical stratosphere in WACCM is dominated by momentum deposition from stationary planetary waves and parameterized gravity waves. The tropical stratosphere is forced by a greater variety of wave modes. Recognizing the importance of gravity wave forcing mechanisms, J. Richter developed, and implemented in WACCM, a physically based source spectrum parameterization for convectively generated gravity waves. This parameterization significantly improves the representation of the stratospheric Semi-Annual Oscillation (SAO) and the mesospheric semi-annual oscillation (MSAO) in WACCM. The true impact, however, is probably underestimated since convectively generated waves are underrepresented in WACCM due to the low variability of tropospheric convection. WACCM3 is successful in reproducing the dominant tidal features in the mesosphere/lower thermosphere such as the diurnal and semidiurnal tide. WACCM’s tides are being compared to a simpler model (GSWM) and observations in collaboration with Loren Chang (graduate student at the University of Colorado), Scott Palo (University of Colorado), and Maura Hagan (HAO). WACCM3 does not represent well the two-day wave. This is due to the fact that the stratospheric/mesospheric shear zones are two weak, not allowing for wave growth in baroclinically unstable regions.