Vertical Propagation of Wave Perturbations in the Middle Atmosphere on Mars by MAVEN/IUVS

Abstract

This work offers the first in‐depth study of the global characteristics of wave perturbations in temperature profiles at 20–140 km altitudes derived from the Imaging Ultraviolet Spectrograph (IUVS) onboard the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. The peak amplitudes of waves seen in temperature profiles exceed 20% of the mean background, especially on the nightside, which is larger than those in Earth's mesosphere and thermosphere. The wave perturbations generate an instability layer around 70–100 km on the nightside, which potentially causes wave‐breaking and turbulences. Our results highlighted a seasonal variation in the latitudinal distribution of nightside perturbations. Amplitudes of wave perturbations were found to be large in the northern low‐latitude region and the southern polar region during the first half of the year (Ls = 0–180°). An increase of waves in the spectral density was found in southern low‐latitude regions in the latter half of the year (Ls = 180–360°). Vertical wavenumber spectral density in the Martian middle atmosphere shows a power‐law dependence with a logarithmic spectral slope of −3, similar to the features seen in the Earth's atmosphere. The derived spectral power density suggests the longer waves growing with height while the effective dissipation of shorter waves occurs. The strong CO2 15‐micron band cooling can effectively dissipate shorter waves. In contrast, the spectral power density at longer waves suggests an amplitude growth with height of unsaturated waves up to the lower thermosphere.

Gravity Wave Activity in the Martian Atmosphere at Altitudes 20–160 km From ACS/TGO Occultation Measurements

“…GWs in the upper thermosphere were also measured by Neutral Gas and Ion Mass Spectrometer (NGIMS) on board MAVEN (England et al., 2017; Terada et al., 2017; Yiğit et al., 2015). Temperature and density disturbances associated with GWs have been remotely retrieved from stellar, solar and radio occultation data as well as from limb observations (Ando et al., 2012; Creasey, Forbes, & Hinson, 2006; Heavens et al., 2020; Hinson et al., 1999; Nakagawa et al., 2020; Wright, 2012).…”

“…The Imaging Ultraviolet Spectrograph (IUVS) on board MAVEN explored the thermospheric layers (100-150 km) (Gröller et al, 2018;Medvedev et al, 2016). Recently, Nakagawa et al (2020) obtained temperature profiles from IUVS data spanning the atmosphere from 20 to 140 km with a vertical sampling better than 6 km. ACS/TGO is the first IR instrument that allows for measuring in the solar occultation mode temperature and density distributions within an even broader range of altitudes (20-160 km).…”

Martian Dust Storms and Gravity Waves: Disentangling Water Transport to the Upper Atmosphere

“…Gravity waves (GWs) are omnipresent in the atmosphere of Mars and continuously disturb it at all heights. Recent observations not only provided ample evidence for their existence, but also determined their seasonal and spatial climatology in the lower (Heavens et al., 2020) and upper atmosphere (Jesch et al., 2019; Leelavathi et al., 2020; Li et al., 2021; Nakagawa et al., 2020; Siddle et al., 2019; Starichenko et al., 2021; Vals et al., 2019; Yiğit, Medvedev, Benna, et al., 2021; Yiğit, Medvedev, & Hartogh, 2021). The main dynamical role of GWs in planetary atmospheres is to re‐distribute momentum and energy between atmospheric layers, thus providing a vertical coupling between the lower and the upper atmosphere (Yiğit & Medvedev, 2015, 2019).…”

Gravity wave activity in the Martian atmosphere at altitudes 20-160 km from ACS/TGO occultation measurements

“…GWs in the upper thermosphere were also measured by Neutral Gas and Ion Mass Spectrometer (NGIMS) on board MAVEN England et al, 2017;Terada et al, 2017). Temperature and density disturbances associated with GWs have been remotely retrieved from stellar, solar and radio occultation data as well as from limb observations (Hinson et al, 1999;Creasey et al, 2006b;Ando et al, 2012;Wright, 2012;Heavens et al, 2020;Nakagawa et al, 2020).…”

“…The Imaging Ultraviolet Spectrograph (IUVS) on board MAVEN explored the thermospheric layers (100-150 km) (Medvedev et al, 2016;Gröller et al, 2018). Recently, Nakagawa et al (2020) obtained temperature profiles from IUVS data spanning the atmosphere from 20 to 140 km with a vertical sampling better than 6 km. ACS/TGO is the first IR instrument that allows for measuring in the solar occultation mode temperature and density distributions within an even broader range of altitudes (20-160 km).…”