Gravity waves play a key role in the vertical coupling of atmosphere regions, because they can impact large-scale flow, induce transport of atmosphere constituents, and cause increasingly large atmospheric perturbations at higher altitudes, including the thermosphere and ionosphere. At the same time they also pose a stiff challenge to the study of vertical coupling, mainly because of the very broad range of spatial and temporal scales of these waves, and the even broader range of scales of the wave impacts, and observations and numerical simulations can only cover a limited range of spatial and temporal scales. The gravity waves in the global context are generally poorly quantified, and they are one of the most important causes of bias and uncertainty in middle and upper atmosphere models. Recent developments of model capability and computing power expand the horizon of gravity wave research, and afford the opportunity to explore increasingly broader scales over the whole atmosphere domain. Recently we have performed Whole Atmosphere Community Climate Model (WACCM) simulations at ~0.25 degree horizontal and 0.1 scale-height vertical resolution. In this talk, I will present results from this simulation. By comparing the simulated gravity waves with available observations, we hope to gain a better understanding of wave energy density and gravity wave momentum flux, including their spatial structures and vertical variation up to the lower thermosphere, their seasonal variation, and their intermittency.

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*email: liuh@ucar.edu
*Preference: Oral