Solar terminator wave in a mars general circulation model

Abstract

A solar terminator wave (TW) is found in highresolution general circulation model (GCM) simulations of Mars' atmosphere. In the horizontal plane at 160 km the wave fronts follow the westward-moving dusk terminator, exhibit a horizontal wavelength of order 1800-3600 km, and are oriented about 10°-30° with respect to the terminator. The disturbance originates in the lower atmosphere due to dust absorption of solar radiation, propagates upward with an effective vertical wavelength of order 60 km, and increases in amplitude as the assumed dust distribution extends further away from the surface. The TW density amplitudes for low and elevated dust layers (both with opacities = 1.0) are of order ±15-20% and ±30% at 160 km. Temperature and wind perturbations for the former case are of order ±10-20K and ±30-75 m/s. The Mars TW shares many common features with a TW recently observed in Earth's thermosphere and simulated with a terrestrial GCM. Copyright 2009 by the American Geophysical Union.