Mars thermospheric scale height: CO Cameron and CO2+ dayglow observations from Mars Express

Stiepen, Arnaud; Gérard, Jean‐Claude; Bougher, S. W.; Montmessin, Franck; Hubert, Benoît; Bertaux, Jean-Loup

doi:10.1016/j.icarus.2014.09.051

Cited by 32 publications

(59 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In addition, vertical profiles of key dayglow emissions observed by Mariners 6, 7, 9, and Mars Express have been used to extract temperatures, especially topside (exosphere) values (e.g. Stewart 1972;Stewart et al 1972;Leblanc et al 2006;Huestis et al 2010;Stiepen et al 2014). Generally, dayside isothermal temperatures are found above ∼160 km for solar minimum conditions, and at higher altitudes for solar moderate-to-maximum conditions (e.g.…”

mentioning

confidence: 99%

The Aeronomy of Mars: Characterization by MAVEN of the Upper Atmosphere Reservoir That Regulates Volatile Escape

et al. 2014

View full text Add to dashboard Cite

The Mars thermosphere-ionosphere-exosphere (TIE) system constitutes the atmospheric reservoir (i.e. available cold and hot planetary neutral and thermal ion species) that regulates present day escape processes from the planet. The characterization of this TIE system, including its spatial and temporal (e.g., solar cycle, seasonal, diurnal, episodic) variability is needed to determine present day escape rates. Without knowledge of the physics and chemistry creating this TIE region and driving its variations, it is not possible to constrain either the short term or long term histories of atmosphere escape from Mars. MAVEN (Mars Atmosphere and Volatile Evolution Mission) will make both in-situ and remote measurements of the state variables of the Martian TIE system. A full characterization of the thermosphere (∼100-250 km) and ionosphere (∼100-400 km) structure (and its variability) will be conducted with the collection of spacecraft in-situ measurements that systematically span most local times and latitudes, over a regular sampling of Mars seasons, and throughout the bottom half of the solar cycle. Such sampling will far surpass that available from existing spacecraft and ground-based datasets. In addition, remote measurements will provide a systematic mapping of the composition and structure of Mars neutral upper atmosphere and coronae (e.g. H, C, N, O), as well as probe lower altitudes. Such a detailed characterization is a necessary first step toward answering MAVEN's three main science questions (see Jakosky et al. 2014, this issue). This information will be used to determine present day escape rates from Mars, and provide an estimate of integrated loss to space throughout Mars history.

show abstract

mentioning

confidence: 99%

The Aeronomy of Mars: Characterization by MAVEN of the Upper Atmosphere Reservoir That Regulates Volatile Escape

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Leblanc et al (2006) reported a very large temperature enhancement of 100K over strong crustal magnetic fields, essentially based on a single observation made over the southern hemisphere. Such a conclusion was not confirmed by the more recent study of Stiepen et al (2015) using a much larger data set covering 10 years of SPICAM observations of dayglow emission in the Martian upper atmosphere. We caution that these early results are based on the scale heights derived from observed emission features of CO 2 + or CO, and therefore reflect change in mean isothermal temperature rather than the change in temperature profile.…”

Section: Temperature Variabilitymentioning

confidence: 67%

“…The thermal structure of the dayside Martian upper atmosphere is well known to be controlled by solar EUV heating, radiative cooling via CO 2 emission, and thermal conduction (e.g., Bougher et al 1999Bougher et al , 2000, but whether or not strong crustal magnetic fields have an impact as well remains unclear (Leblanc et al 2006;Stiepen et al 2015). By analyzing the MAVEN NGIMS measurements of CO 2 during several DD campaigns that sample the southern hemisphere of Mars, we are able to compare the mean temperature profiles obtained over regions with strong crustal magnetic fields and those obtained over regions without.…”

Section: Discussionmentioning

confidence: 99%

“…Previous attempts to search for the impact of crustal magnetic fields on neutral temperature were made by Leblanc et al (2006) and Stiepen et al (2015), both using the dayglow emission data acquired by the MEx SPICAM instrument. Leblanc et al (2006) reported a very large temperature enhancement of 100K over strong crustal magnetic fields, essentially based on a single observation made over the southern hemisphere.…”

Section: Temperature Variabilitymentioning

confidence: 99%

“…In addition, crustal magnetic fields likely affect local plasma distribution (Andrews et al 2014) and accordingly local heating via exothermic ion chemistry (e.g., Fox 1988). Search for the impact of crustal magnetic fields on the thermal structure of the dayside Martian upper atmosphere was attempted based on the dayglow emission data acquired by the Mars Express (MEx) Spectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars (SPICAM), but no firm conclusion was reached (Leblanc et al 2006;Stiepen et al 2015).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Cui

Yelle

Zhao

et al. 2018

ApJL

View full text Add to dashboard Cite

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.

show abstract

The equivalent slab thickness of Mars' ionosphere: Implications for thermospheric temperature

Mendillo

Narvaez

Lawler

et al. 2015

Geophysical Research Letters

View full text Add to dashboard Cite

The total electron content (TEC) of a planetary ionosphere is dominated by plasma near and above the height of maximum electron density (Nmax). The ratio TEC/Nmax represents the thickness (τ) of a TEC slab of uniform density (Nmax). For a photochemical ionosphere, τ relates to the scale height (H = kT/mg) of the ionized neutral gas as τ ~ 4 × H. Derived temperatures refer to ~160 km in thermosphere height—below the asymptotic temperature of the exosphere. The MARSIS instrument on Mars Express has produced data sets of TEC and Nmax. We used them to form τ patterns versus solar zenith angle and solar cycle phase. For daytime (SZA < 90°) conditions, <τ > day ~ 50 km, decreasing rapidly for solar zenith angle (SZA) > 90° to < τ > night ~ 25 km. These correspond to Tn values of 250°K and 125°K. Using Mars Global Surveyor data, τ patterns show a mild dependence upon the solar EUV flux proxy F10.7, with ΔTn(°K) ~ 0.3° per unit change in F10.7 at Mars.

show abstract

Mars thermospheric scale height: CO Cameron and CO2+ dayglow observations from Mars Express

Cited by 32 publications

References 42 publications

The Aeronomy of Mars: Characterization by MAVEN of the Upper Atmosphere Reservoir That Regulates Volatile Escape

The Aeronomy of Mars: Characterization by MAVEN of the Upper Atmosphere Reservoir That Regulates Volatile Escape

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

The equivalent slab thickness of Mars' ionosphere: Implications for thermospheric temperature

Contact Info

Product

Resources

About