Observations of Gravity Waves in the Middle Atmosphere of Mars

Saunders, William R.; Withers, Paul

doi:10.3847/1538-3881/abf1ef

Cited by 5 publications

(4 citation statements)

References 68 publications

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“…By comparing the original normalized temperature perturbation with the reconstructed one using the dominant wave amplitude in Figure 2(b), we can note that the extracted amplitudes and phases clearly portray the perturbation of the dominant wave. Also, note that the amplitudes of the wave-induced temperature perturbations are less than 15% of the mean background temperature and the mean vertical wavelengths are around 30 km, which are consistent with previous findings (Saunders et al 2021;Wu et al 2022b). Figures 2(c)-(d) are identical, but for orbit 9393 in MY35, with the tangent points of the occultation located at (161.5°W,25.2°S) and L s = 128°.8.…”

Section: Procedures For Extracting Gw Perturbations Fromsupporting

confidence: 90%

“…However, their results are confounded with the effect of thermal tides, due to the limitations of the data resolution. Saunders et al (2021) described the GWs in the middle atmosphere using 12 high-resolution atmospheric density profiles measured by ground-based stellar occultation and during atmospheric entry by landers and rovers. They found that the dominant wavelengths of GWs were 3-14 km and the amplitudes were 0.8%-2.5%.…”

Section: Introductionmentioning

confidence: 99%

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Climatological Gravity Waves in the Middle and Upper Atmosphere of Mars Based on ACS/TGO Observations

Zhu

Sheng

et al. 2023

ApJ

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Gravity waves (GWs) are important for the vertical coupling of the Martian atmosphere. The middle atmosphere is the key region where GWs propagate to the upper thermosphere and generate momentum and energy exchange, but the knowledge of middle-atmosphere GWs is incomplete, due to the lack of observations with the kilometer-scale resolution. We have analyzed the climatology of GW activity in the middle and upper atmosphere of Mars using 20–180 km temperature profiles measured by the Atmospheric Chemistry Suite instrument on board the Trace Gas Orbiter. The results show that the amplitudes of GWs extracted in this study are generally less than 15% and that the centers of the strongest GW activity vary significantly with the seasons. Second, the strongest GW activity in the mesosphere indicates the strong dissipation effects of the mesopause, and the mid-atmospheric GWs show a seasonal pattern that is stronger in the winter hemisphere. During the global dust event of MY34, the enhancement of GWs in the middle atmosphere is most pronounced at low and middle latitudes where the dust storms are active. It is possible that changes in the temperature structure of the middle atmosphere adjust the atmospheric circulation and thus improve the propagation of GWs. Furthermore, GW activity is stronger on the dayside than on the nightside, and there is no significant correlation between amplitudes and background temperature. This suggests a limited role of convective instability in limiting the growth of GWs in the middle atmosphere, with nonlinear damping competing with that of molecular diffusion at different harmonics.

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Section: Procedures For Extracting Gw Perturbations Fromsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Climatological Gravity Waves in the Middle and Upper Atmosphere of Mars Based on ACS/TGO Observations

Zhu

Sheng

et al. 2023

ApJ

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“…The mesosphere of Mars is the region of the atmosphere from around 50–100 km and is currently one of the main regions of interest where several important atmospheric phenomena occur such as gravity waves (Nakagawa, Terada, et al., 2020; Saunders et al., 2021; Starichenko et al., 2021) and/or tides (England et al., 2019; Gröller et al., 2018; Jain et al., 2021; Nakagawa, Jain, et al., 2020). The mesosphere is the coldest region in the atmosphere of Mars and the temperature can be so low that CO 2 freezes into ice clouds (Liuzzi et al., 2021).…”

Section: Introductionmentioning

confidence: 99%

Carbon Dioxide Retrievals From NOMAD‐SO on ESA's ExoMars Trace Gas Orbiter and Temperature Profiles Retrievals With the Hydrostatic Equilibrium Equation: 1. Description of the Method

et al. 2023

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The Solar Occultation (SO) channel of the Nadir and Occultation for Mars Discovery (NOMAD) instrument has been scanning the Martian atmosphere for almost 2 Martian years. In this work, we present a subset of the NOMAD SO data measured at the mesosphere at the terminator. From the data set, we investigated 968 vertical profiles of carbon dioxide density and temperature covering the Martian Year (MY) 35 as well as MY 36 up to a solar longitude (Ls) of 135° and altitudes around 60–100 km. While carbon dioxide density profiles are directly retrieved from the spectral signature in the spectra, temperature profiles are more challenging to retrieve as unlike density profiles, temperature profiles can present some spurious features if the regularization is not correctly managed. Comparing seven regularization methods, we found that the expected error estimation method provides the best regularization parameters. The vertical resolution of the profiles is on average 1.6 km. Numerous warm layers and cold pockets appear in this data set. The warm layers are found in the Northern hemisphere at dawn and dusk as well as in the Southern hemisphere at dawn. Strong warm layers are present in more than 13.5% of the profiles. The Southern hemisphere at dusk does not present any warm layer between Ls 50° and 150°. The height and latitudinal distribution of those warm layers were similar in MY 35 and MY 36 during the first half of the year (Ls = 0°–135°).

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“…The mesosphere of Mars is the subject of many recent studies related to tides (England et al., 2019; Jain et al., 2021; Nakagawa et al., 2020b), gravity waves (Saunders et al., 2021; Starichenko et al., 2021), CO 2 ice clouds (Liuzzi et al., 2021) and an intense warm layer present in the night side (Nakagawa et al., 2020a).…”

Section: Introductionmentioning

confidence: 99%

Carbon Dioxide Retrievals From NOMAD‐SO on ESA's ExoMars Trace Gas Orbiter and Temperature Profile Retrievals With the Hydrostatic Equilibrium Equation: 2. Temperature Variabilities in the Mesosphere at Mars Terminator

et al. 2023

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The Solar Occultation (SO) channel of the Nadir and Occultation for Mars Discovery (NOMAD) instrument scans the Martian atmosphere since 21 April 2018. In this work, we present a subset of the NOMAD SO data measured at the mesosphere. We focused on a spectral range that started to be recorded in Martian year (MY) 35. A total of 968 vertical profiles of carbon dioxide density and temperature covering MY 35 and the beginning of MY 36 were investigated until 135° of solar longitude. We compared 47 profiles with co‐located profiles of the Mars Climate Sounder onboard the Mars Reconnaissance Orbiter. Most profiles show a good agreement as SO temperatures are only 1.8 K higher, but some biases lead to an average absolute difference of 7.4°K. The SO data set is also compared with simulations from the Global Environmental Multiscale‐Mars general circulation model. Both data sets are in good agreement except for the presence of a cold layer in the winter hemisphere and a warm layer at dawn in the Northern hemisphere for solar longitudes between 240° and 360°. Five profiles contain temperatures lower than the limit for CO2 condensation. Strong warm layers were found in 13.5% of the profiles. They are present mainly at dawn and in the winter hemisphere, while the Northern dusks appear featureless. The data set mainly covers high latitudes around 60° and we derived some non‐migrating tides. In the Southern winter hemisphere, we derived apparent zonal wavenumber‐1 (WN‐1) and WN‐3 tidal components with a maximum amplitude of 10% and 5% at 63 km, respectively.

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Observations of Gravity Waves in the Middle Atmosphere of Mars

Cited by 5 publications

References 68 publications

Climatological Gravity Waves in the Middle and Upper Atmosphere of Mars Based on ACS/TGO Observations

Climatological Gravity Waves in the Middle and Upper Atmosphere of Mars Based on ACS/TGO Observations

Carbon Dioxide Retrievals From NOMAD‐SO on ESA's ExoMars Trace Gas Orbiter and Temperature Profiles Retrievals With the Hydrostatic Equilibrium Equation: 1. Description of the Method

Carbon Dioxide Retrievals From NOMAD‐SO on ESA's ExoMars Trace Gas Orbiter and Temperature Profile Retrievals With the Hydrostatic Equilibrium Equation: 2. Temperature Variabilities in the Mesosphere at Mars Terminator

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