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Measurements of CO2, Ar, N2, and O densities between 150 and 200 km from the Mars Atmosphere and Volatile Evolution Neutral Gas and Ion Mass Spectrometer during February 2015 to February 2022 are analyzed to provide a comprehensive analysis of their longitudinal wavenumber k = 1, 2, and 3 components. Variations in density amplitudes (Ak) with solar flux are marginally detectable during this period. The Ak binned and averaged in latitude, local solar time and Ls are referenced to diurnal- and zonal-mean backgrounds in accord with how tides and stationary planetary waves (SPWs) are defined in theory and modeling. The resulting global Ak distributions are the interference patterns formed by superposition of diurnal tides, SPWs and/or semidiurnal tides; consequently, a simple dependence on species mass consistent with thermal expansion (diffusive equilibrium) that might exist for some individual wave components is obscured. Additionally, vertical winds likely contribute to deviations from diffusive equilibrium. Complementary analyses of the Mars Climate Database indicate that the major contributors to the Ak are DE2, SE1, DE1, and SPW1, 2, 3; support the absence of significant variability due to solar flux; and indicate a more well-defined sensitivity to species mass. The Ak and their phases (longitudes of maxima) for the whole data set are available as part of Supporting Information S1. [ABSTRACT FROM AUTHOR]

Measurements of CO2, Ar and N2 densities from the Neutral Gas and Ion Mass Spectrometer on the Mars Atmosphere and Volatile Evolution Mission (MAVEN) between 150 and 200 km altitude during 2015–2022 are analyzed to reveal diurnal (DW1), semidiurnal (SW2) and terdiurnal (TW3) solar‐synchronous tides in Mars thermosphere. Multi‐year‐mean tidal perturbations on a diurnal‐ and zonal‐mean background, corrected for solar flux variations, are reported as a function of latitude (48°S–48°N), altitude and solar longitude (Ls). The DW1, SW2 and TW3 amplitudes at for example, 180 km altitude are of order 90%–120%, 15%–20%, and ≲10% for CO2 and Ar, and roughly 2/3 these values for N2, the latter presumably due to the difference in molecular weight from the other species. Through examination of vertical phase progressions, DW1 is concluded to be mainly excited in situ, but SW2 and TW3 contain significant contributions from tides propagating upward from lower altitudes. By analogy with studies for Earth's thermosphere, the DW1 amplitudes and phases are thought to reflect the combined influences of thermal expansion and vertical winds. Points of agreement and disagreement with DW1, SW2, and TW3 amplitudes and phases derived from the Mars Climate Database are noted and interpreted. Key Points: Global‐scale solar‐synchronous tides are derived from Mars Atmosphere and Volatile Evolution Mission/Neutral Gas and Ion Mass Spectrometer measurements of CO2, Ar, and N2 at Mars, 150–200 kmThe diurnal tide originates mainly in situ; semidiurnal and terdiurnal tides show evidence of upward propagation from belowPoints of agreement and disagreement with the Mars Climate Database are noted and interpreted [ABSTRACT FROM AUTHOR]

The nature and origins of longitudinal density structures in Mars' thermosphere between 100 and 120 km altitude, and -30° and -75° latitude around winter solstice (Ls = 70--122°), as measured by the accelerometer on the ExoMars Trace Gas Orbiter (TGO) Mission, are investigated. The methodology consists of deducing the responsible waves by comparing the observed longitude versus local time phase progressions of the structures with those of probable candidate waves in the Mars Climate Database (MCD) climatology. The observed wave-1, wave-2, and wave-3 structures are interpreted as originating mainly from SPW1; (SPW2, S0, DE1); and (SPW3, DE2), respectively, where SPWm denotes a stationary planetary wave with zonal wavenumber s = m, S0 is the zonally symmetric semidiurnal tide, and DE1(DE2) are the eastward-propagating diurnal tides with s = -1(-2). All of these waves exist in the MCD with amplitudes as large as those observed, although not wholly in the narrow height-latitude regime accessed by TGO. This disparity between the MCD and TGO amplitude structures is hypothesized to result from the extreme intrusion of the polar-region eastward winter jet into the thermosphere in the MCD. The winter polar jet blocks poleward expansion of DE1 and DE2 beyond -30° latitude, and also impacts the structures of SPW2, S0 and SPW3 that arise from in situ nonlinear interaction between DE1 and DE2, respectively, with the diurnal migrating tide (DW1). [ABSTRACT FROM AUTHOR]

The nature and origins of longitudinal density structures in Mars’ thermosphere between 100 and 120 km altitude, and −30° and −75° latitude around winter solstice (Ls = 70–122°), as measured by the accelerometer on the ExoMars Trace Gas Orbiter (TGO) Mission, are investigated. The methodology consists of deducing the responsible waves by comparing the observed longitude versus local time phase progressions of the structures with those of probable candidate waves in the Mars Climate Database (MCD) climatology. The observed wave‐1, wave‐2, and wave‐3 structures are interpreted as originating mainly from SPW1; (SPW2, S0, DE1); and (SPW3, DE2), respectively, where SPWm denotes a stationary planetary wave with zonal wavenumber s = m, S0 is the zonally symmetric semidiurnal tide, and DE1(DE2) are the eastward‐propagating diurnal tides with s = −1(−2). All of these waves exist in the MCD with amplitudes as large as those observed, although not wholly in the narrow height‐latitude regime accessed by TGO. This disparity between the MCD and TGO amplitude structures is hypothesized to result from the extreme intrusion of the polar‐region eastward winter jet into the thermosphere in the MCD. The winter polar jet blocks poleward expansion of DE1 and DE2 beyond −30° latitude, and also impacts the structures of SPW2, S0 and SPW3 that arise from in situ nonlinear interaction between DE1 and DE2, respectively, with the diurnal migrating tide (DW1).Key Points: Longitudinal density structures measured by Mars TGO accelerometer are interpreted with insights provided by Mars Climate Database (MCD)Stationary planetary waves, some excited by in situ wave‐wave interactions, play a prominent role in explaining the density structuresThe MCD‐TGO comparison suggests that the intensity and vertical‐latitudinal extent of the winter polar jet may be overestimated in the MCD [ABSTRACT FROM AUTHOR]