Gravity waves simulated by high-resolution Whole Atmosphere Community Climate Model

Abstract:

Gravity waves play a key role in the vertical coupling of atmosphere regions, because
they can carry momentum flux from their source region to where they are dissipated and
thus alter the large-scale flow and can 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 usually 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. However, the recent development of model capability and computing
power is expanding the horizon of gravity wave research, and affording 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. I will focus on evaluating various gravity wave quantities against previous
observational and numerical studies, including the wave spectrum, wave energy density and
their spatial distribution, and wave forcing in the middle and upper atmosphere.