Comparison of the Martian thermospheric density and temperature from IUVS/MAVEN data and general circulation modeling

Medvedev, Alexander S.; Nakagawa, Hiromu; Mockel, Chris; Yiğit, Erdal; Kuroda, Takeshi; Hartogh, P.; Terada, K.; Terada, Naoki; Seki, K.; Schneider, Nicholas M.; Jain, Sonal; Evans, J. S.; Deighan, Justin; McClintock, W. E.; Lo, Daniel; Jakosky, B. M.

doi:10.1002/2016gl068388

Cited by 38 publications

(50 citation statements)

References 41 publications

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“…The different conclusions about the relative importance of m = 2 and m = 3 tides in Lo et al () and Medvedev et al () from the same data set may be related to that fact that Lo et al () based their analysis on the peak altitude of the observed intensities, whereas Medvedev et al () relied on the CO 2 densities derived from the emissions. In principle, these two approaches should give the same results and the differences between Lo et al () and Medvedev et al () merit further investigation. It is worth noting that the coverage of the emission and density data sets differ because not all emission profiles can be confidently converted to density.…”

Section: Resultsmentioning

confidence: 92%

“…In contrast with Lo et al () and England et al (), but consistent with the results reported here, they find that longitude perturbations are dominated by m = 3. No Fourier analysis is presented in the paper, and this statement is based on visual inspection of Figure 3 of Medvedev et al (). The perturbation amplitudes calculated by Medvedev et al () appear to be approximately a factor 2, significantly larger than found by Lo et al () and England et al () but consistent with the δ Sco occultation results.…”

Section: Resultsmentioning

confidence: 99%

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MAVEN/IUVS Stellar Occultation Measurements of Mars Atmospheric Structure and Composition

et al. 2018

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The Imaging UltraViolet Spectrograph (IUVS) instrument of the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission has acquired data on Mars for more than one Martian year. During this time, beginning with March 2015, hundreds of stellar occultations have been observed, in 12 dedicated occultation campaigns, executed on average every 2 to 3 months. The occultations cover the latitudes from 80°S to 75°N and the full range longitude and local times with relatively sparse sampling. From these measurements we retrieve CO2, O2, and O3 number densities as well as temperature profiles in the altitude range from 20 to 160 km, covering 8 orders of magnitude in pressure from ∼2 × 101 to ∼4 × 10−7 Pa. These data constrain the composition and thermal structure of the atmosphere. The O2 mixing ratios retrieved during this study show a high variability from 1.5 × 10−3 to 6 × 10−3; however, the mean value seems to be constant with solar longitude. We detect ozone between 20 and 60 km. In many profiles there is a well‐defined peak between 30 and 40 km with a maximum density of 1–2 ×109 cm−3. Examination of the vertical temperature profiles reveals substantial disagreement with models, with observed temperatures both warmer and colder than predicted. Examination of the altitude profiles of density perturbations and their variation with longitude shows structured atmospheric perturbations at altitudes above 100 km that are likely nonmigrating tides. These perturbations are dominated by zonal wave numbers 2 and 3 with amplitudes greater than 45%.

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Section: Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 99%

MAVEN/IUVS Stellar Occultation Measurements of Mars Atmospheric Structure and Composition

et al. 2018

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“…Many modeling studies have simulated DE1 and DE2 tides and revealed their importance in controlling the longitudinal structures in the thermosphere [e.g., Bougher et al, ; Angelats i Coll et al, ; Wilson, ; Forbes and Miyahara , ; Moudden and Forbes , , ; Medvedev et al , ]. Some of these studies have found that the density amplitudes caused by these tides are ~20% at Ls = 30 – 90° in the tropics [ Bougher et al, ; Angelats i Coll et al, ; Forbes and Miyahara , ].…”

Section: Longitudinal Structuresmentioning

confidence: 99%

Longitudinal structures in Mars' upper atmosphere as observed by MAVEN/NGIMS

et al. 2017

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Here we report the first comprehensive study of longitudinal structures in Mars' neutral upper atmosphere associated with atmospheric tides in composition, density and temperature using the Mars Atmosphere and Volatile Evolution Mission/Neutral Gas Ion Mass Spectrometer observations during 2015. These are in situ measurements of number densities of atmospheric species (including CO2, Ar, N2, and CO) in the altitude range from 120 to 200 km above the areoid (corresponding to a total density range from ~108–1011 cm−3), providing a data set that is larger than all previous measurements of these waves combined. These observations span from ±70° latitude and cover a wide range of local times and solar longitudes (Ls), allowing for the study of longitudinal structures under various conditions. Furthermore, the data in May and November 2015 are at similar latitudes and local times but different Ls (~340° in May, close to northern spring equinox, and 70° in November, close to northern summer solstice and aphelion), ideal for studying the seasonal effects of tides. Our analysis shows that in each month the Ar density varies with longitude having a large wave structure. It is dominated by wave 2 and 3, accounting for 8–16% of the change of the mean density. Comparison shows that the longitudinal structures at a constant CO2 density level have different amplitudes at different seasons, although their patterns are similar. The temperature structure has a phase difference from the density variation, indicating the dissipation of tides in this altitude region. The longitudinal structure is seen in all species, including major and minor species, consistent with the tidal signatures.

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“…The largest difference is seen for DD2 with the mean O mixing ratio for CF depleted by as much as 20% above 180km relative to NCF, but cooling at such high altitudes is dominated by thermal conduction and horizontal advection, rather than CO 2 emission (e.g., Bougher et al 2009). Finally, non-migrating tides, which originate in the lower atmosphere and owe their existence to the topography of Mars (e.g., Forbes & Hagan 2000), provide a source of longitudinal variability in the Martian upper atmosphere (Lo et al 2015;Medvedev et al 2016). Such a possibility is also easily ruled out since the temperature variations produced by topography and crustal magnetization have different longitudinal patterns.…”

Section: Temperature Variabilitymentioning

confidence: 99%

The Impact of Crustal Magnetic Fields on the Thermal Structure of the Martian Upper Atmosphere

Cui

Yelle

Zhao

et al. 2018

ApJL

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Using the Mars Atmosphere and Volatile Evolution Neutral Gas and Ion Mass Spectrometer data, we investigate the possible impact of crustal magnetic fields on the thermal structure of the Martian upper atmosphere. Our analysis reveals a clear enhancement in temperature over regions with strong crustal magnetic fields during two deep dip campaigns covering the periods of April 17-22 and September 2-8, both in 2015. Several controlling factors, such as solar EUV irradiance, relative atomic O abundance, and non-migrating tides, do not help to explain the observed temperature enhancement, and a magnetically driven scenario is favored. We evaluate the roles of several heating mechanisms that are likely modulated by the presence of crustal magnetic fields, including Joule heating, ion chemical heating, as well as electron impact heating via either precipitating solar wind electrons or locally produced photoelectrons. The respective heating rates of these mechanisms are substantially lower than the solar EUV heating rate, implying that none of them is able to interpret the observations.

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Comparison of the Martian thermospheric density and temperature from IUVS/MAVEN data and general circulation modeling

Cited by 38 publications

References 41 publications

MAVEN/IUVS Stellar Occultation Measurements of Mars Atmospheric Structure and Composition

MAVEN/IUVS Stellar Occultation Measurements of Mars Atmospheric Structure and Composition

Longitudinal structures in Mars' upper atmosphere as observed by MAVEN/NGIMS

The Impact of Crustal Magnetic Fields on the Thermal Structure of the Martian Upper Atmosphere

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