Migrating Thermal Tides in the Martian Atmosphere during Aphelion Season Observed by EMM/EMIRS

TL;DR

This study analyzes migrating thermal tides in the Martian atmosphere during aphelion using EMIRS data from the Emirates Mars Mission, revealing dominant diurnal and semi-diurnal tides with specific amplitude and wavelength characteristics.

Contribution

It provides new observational insights into Martian thermal tides during aphelion, utilizing the unique orbit design of the Hope Probe for improved coverage.

Findings

Dominant diurnal tide with 6K amplitude

Semi-diurnal tide with 2K amplitude and ~200km wavelength

Agreement with Mars PCM model, but with phase and wavelength discrepancies

Abstract

Temperature profiles retrieved using the first set of data of the Emirates Mars InfraRed Spectrometer (EMIRS) obtained during the science phase of the Emirates Mars Mission (EMM) are used for the analysis of migrating thermal tides in the Martian atmosphere. The selected data cover a solar longitude (LS) range of 60{\deg}-90{\deg} of Martian Year (MY) 36. The novel orbit design of the Hope Probe leads to a good geographic and local time coverage that significantly improves the analysis. Wave mode decomposition suggests dominant diurnal tide and important semi-diurnal tide with maximal amplitudes of 6K and 2K, respectively, as well as the existence of ~0.5K ter-diurnal tide. The results agree well with predictions by the Mars Planetary Climate Model (PCM), but the observed diurnal tide has an earlier phase (3h), and the semi-diurnal tide has an unexpectedly large wavelength (~200km).