Analysis of Planetary Scale Waves Using Idealized Sudden Stratospheric Warming Simulations in Different Dynamical Cores

Planetary waves from the troposphere are known to play an important role in sudden stratospheric warming (SSW). To evaluate the representation of large-scale waves in idealized SSW simulations, three dynamical cores of the National Center for Atmospheric Research Community Atmosphere Model were tested in this study: the Eulerian (EUL) spectral-transform, finite-volume (FV), and spectral element (SE) models. Notable differences were observed among the dynamical cores, with FV being unable to generate major SSWs and simulating minor SSWs less effectively than the other models. Wave decomposition analysis revealed distinct planetary wave propagation patterns during the development of each event. Zonal Wave Number 2 wave activities primarily determined SSW types, and ZWN1 led SSWs to recovery during the ensuing periods. However, FV failed to adequately propagate large-scale waves in minor SSW events, preventing the reversal of stratospheric zonal-mean zonal winds. Interestingly, FV showed decreased upward Eliassen–Palm flux compared to that of other dynamical cores, even during climatology. Additional tests were performed to examine the reasons for FV's atypical results, but the dynamic impacts on planetary waves remain poorly understood.