Stationary planetary waves in the atmosphere of Mars during southern winter

[1] We report new observations of stationary planetary waves in the Southern Hemisphere of Mars by Mars Global Surveyor (MGS). We focus on a period during midwinter (Ls = 134 –160 ) when independent observations were acquired by two techniques. Radio occultation experiments sounded the atmosphere at essentially fixed latitude ( 68 S) and local time ( 1030), yielding profiles of geopotential and temperature between the surface and the 9 Pa pressure level. Observations by the Thermal Emission Spectrometer (TES) included systematic limb sounding at nine discrete latitudes and two local times ( 0200 and 1500), yielding temperature profiles at pressures of 1–100 Pa. We supplemented these data with a simulation by a Mars general circulation model (MGCM), which provides an accurate synthesis of the observations. These stationary planetary waves have significant amplitudes at zonal wave numbers s = 1 and 2. The s = 1 component propagates vertically, as reflected by a westward tilt with increasing height in the geopotential and temperature fields and a net poleward eddy heat flux. The peak amplitude at s = 1 is 1 km in geopotential height and 7 K in temperature. The geopotential field of the s = 2 component is ‘‘barotropic’’ in character, which results through hydrostatic balance in a distinctive temperature field. The peak amplitude at s = 2 is 700 m in geopotential height and 4–6 K in temperature.