Observations of planetary waves and nonmigrating tides by the Mars Climate Sounder

Abstract

Temperature profiles from the Mars Reconnaissance Orbiter's (MRO) Mars Climate Sounder (MCS) indicate the presence of several types of stationary planetary waves and nonmigrating thermal tides in the Martian atmosphere. We analyze 35 months of MCS data to identify the dominant waves. With the contribution of the zonal mean and migrating tides removed, the temperature perturbations remaining are due to planetary waves, nonmigrating tides, and topographic and surface albedo/thermal inertia effects. We characterize waves with satellite‐relative wave numbers 1 through 4 in the Martian middle atmosphere (40–80 km). In tropical latitudes, eastward propagating diurnal Kelvin waves are the dominant component observed in the satellite‐relative wave number 2 through 4 fields; we identify these as diurnal Kelvin waves 1 through 3, respectively. The Kelvin waves have very long vertical wavelengths and amplitudes of 1–3 K. This is the first unambiguous detection of diurnal Kelvin wave 3. We also identify the zonally symmetric diurnal tide and an eastward propagating semidiurnal wave 1 tide, possibly the semidiurnal Kelvin wave 1. Stationary planetary waves with wave numbers 1 and 2 produce 5–10 K amplitudes in the middle and high latitudes of both hemispheres.