Secular variations of atomic oxygen in the mesopause region induced by transient gravity wave packets

Abstract

We employ a 2‐dimensional, time‐dependent, fully nonlinear model of minor species in the mesopause region and our Spectral Full‐Wave Model to simulate the response of atomic oxygen (O) to a gravity wave packet in the mesopause region. We demonstrate that gravity waves affect the time‐averaged distribution of O in the mesosphere and lower thermosphere (MLT) region through the constituent fluxes the waves induce. Our conclusions are based on simulations of two wave packets that violate the non‐acceleration conditions through transience and dissipation. The net cycle‐averaged effect of the waves is to significantly increase (by as much as 50%) the O density through downward transport of O at low altitudes (≤90 km), and to deplete (by as much as 20%) the O density above ∼100 km altitude. Comparison with results obtained including only chemistry and diffusion suggests that the effects of gravity wave transport on the distribution of O in this region can be greater than the effects of eddy transport.