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

We employ a 2-dimensional, time-dependent, fully nonlinear model of minor s pecies 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 mesopaus e region. We demonstrate that gravity waves, affect the time-averaged distr ibution of O in the mesosphere and lower thermosphere (MLT) region through the constituent fluxes the waves induce. Our conclusions are based on simul ations of two wave packets that violate the non-acceleration conditions thr ough transience and dissipation. The net cycle-averaged effect of the waves is to significantly increase (by as much as 50%) the O density through dow nward transport of O at low altitudes (less than or equal to 90 km), and to deplete (by as much as 20%) the O density above similar to 100 km altitude . Comparison with results obtained including only chemistry and diffusion s uggests that the effects of gravity wave transport on the distribution of O in this region can be greater than the effects of eddy transport.