Thermal Tides in the Martian Atmosphere Near Northern Summer Solstice Observed by ACS/TIRVIM Onboard TGO

Thermal tides in the Martian atmosphere are analyzed using temperature profiles retrieved from nadir observations obtained by the TIRVIM Fourier-spectrometer, part of the Atmospheric Chemistry Suite onboard the ExoMars Trace Gas Orbiter. The data is selected near the northern summer solstice at solar longitude (L-S) 75 degrees-105 degrees of Martian Year 35. The observations have a full local time coverage, which enables analyses of daily temperature anomalies. The observed zonal mean temperature is lower by 4-6 K at similar to 100 Pa, but higher toward the summer pole, compared to the Laboratoire de Meteorologie Dynamique (LMD) Mars General Circulation Model (GCM). Wave mode decomposition shows dominant diurnal tide and important semi-diurnal tide and diurnal Kelvin wave, with maximal amplitudes of 5, 3, and 2.5 K, respectively, from tens to hundreds of Pa. The results generally agree well with the LMD Mars GCM, but with noticeable earlier phases of diurnal (similar to 1 hr) and semi-diurnal (similar to 3 hr) tides.