Diurnal Kelvin wave in the atmosphere of mars: Towards an understanding of'stationary' density structures observed by the MGS accelerometer

Mars Global Surveyor (MGS) accelerometer measurements near 125 km [Keating et al., 1998] reveal longitudinal density structures comprised of zonal wav enumbers s = 1 and s = 2 which are interpreted as stationary waves. An alte rnative interpretation is that these structures may be nonmigrating tides w hich appear as quasistationary features due to restricted sampling in local time, and which owe their existence to Mars' topography. One of these osci llations, the diurnal Kelvin wave, is investigated here. It gives rise to d ensity perturbations similar to the measurements. Other nonmigrating tides may also make important contributions.