The nature of the synoptic period variations in the Viking 2 pressure, wind and temperature data is investigated, using time-spectral and cross-spectral analysis, for selected portions of the Mars fall, winter and spring seasons. Estimates of the phase relationships between the highly coherent pressure, wind and temperature oscillations are obtained, and are very similar to those expected for baroclinic waves, and to these obtained from terrestrial surface data. Phase speeds and zonal wavenumbers are inferred by interpreting the pressure and meridional wind variations in terms of eastward traveling, quasi-geostrophic waves. The calculated phase speeds are on the order of 5–15 m s−1, consistent with the baroclinic wave interpretation, while the wavenumbers of the two dominant fall and spring periodicities are approximately 2 and 4 (the smaller value corresponding to the longer period of 6–8 Mars solar days or sols, and the larger to a 3-sol wave). These wavelengths are in general agreement with th... Abstract The nature of the synoptic period variations in the Viking 2 pressure, wind and temperature data is investigated, using time-spectral and cross-spectral analysis, for selected portions of the Mars fall, winter and spring seasons. Estimates of the phase relationships between the highly coherent pressure, wind and temperature oscillations are obtained, and are very similar to those expected for baroclinic waves, and to these obtained from terrestrial surface data. Phase speeds and zonal wavenumbers are inferred by interpreting the pressure and meridional wind variations in terms of eastward traveling, quasi-geostrophic waves. The calculated phase speeds are on the order of 5–15 m s−1, consistent with the baroclinic wave interpretation, while the wavenumbers of the two dominant fall and spring periodicities are approximately 2 and 4 (the smaller value corresponding to the longer period of 6–8 Mars solar days or sols, and the larger to a 3-sol wave). These wavelengths are in general agreement with th...