The atmospheric temperatures over Olympus Mons on Mars: An atmospheric hot ring

Wolkenberg, P.; Formisano, V.; Rinaldi, G.; Geminale, A.

doi:10.1016/j.icarus.2009.11.005

Cited by 7 publications

(3 citation statements)

References 23 publications

(35 reference statements)

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“…Subsidence is a factor known to shape the lower atmospheric thermal structure of tropical cyclones (Schubert et al, ) and may have implications for the thermodynamics of the circulations involved. A role for subsidence driven by downslope winds from the Tharsis Montes themselves cannot be excluded (Wolkenberg et al, ) but would be unusual in daytime hours (Benson et al, ; Hunt et al, ; Michaels et al, ; Rafkin et al, ; Spiga & Forget, ) unless tidal forcing is sufficient to oppose the typical daytime upslope flow (Rafkin & Michaels, ).…”

Section: Discussionmentioning

confidence: 99%

Dusty Deep Convection in the Mars Year 34 Planet‐Encircling Dust Event

2019

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Dusty convection, convective activity powered by radiative heating of dust, is a ubiquitous phenomenon in Mars's atmosphere but is especially deep (i.e., impactful on the middle atmosphere) and widespread during planet‐encircling dust events (PEDEs) that occur every few Mars Years (MYs). Yet the relative roles of dusty deep convection and global dynamics, such as the principal meridional overturning cell and the radiative tides, in dust storm development and the vertical transport of dust and water are still unclear. Here, observations from the Mars Climate Sounder on board Mars Reconnaissance Orbiter (MRO‐MCS) are used to study dusty deep convection and its impact on middle atmospheric water content during the MY 34 PEDE (commenced June 2018). Additional context is provided by MRO‐MCS observations of the MY 28 PEDE (commenced June 2007). This investigation establishes that a few, localized centers of dusty deep convection in the tropics formed in the initial phases of both PEDE simultaneously with a substantial increase in middle atmospheric water content. The growth phase of the MY 34 PEDE was defined by episodic outbreaks of deep convection along the Acidalia and Utopia storm tracks as opposed to less episodic, more longitudinally distributed convective activity during the MY 28 PEDE. The most intense convection during both PEDE was observed in southern/eastern Tharsis, where MRO‐MCS observed multiple instances of deep convective clouds transporting dust to altitudes of 70–90 km. These results suggest that Martian PEDE typically contain multiple convectively active mesoscale weather systems.

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Section: Discussionmentioning

confidence: 99%

Dusty Deep Convection in the Mars Year 34 Planet‐Encircling Dust Event

2019

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“…Here, the ambient pressure at the surface is low with 6 mbar on average. It varies from below 1 mbar at the highest volcanic elevations to beyond 10 mbar in deep valleys (Wolkenberg et al 2010;Lewis 2003). The question is if this low pressure is beneficial or disadvantageous for generating large scale discharges.…”

Section: Introductionmentioning

confidence: 99%

A challenge for martian lightning: Limits of collisional charging at low pressure

Wurm

Schmidt

Steinpilz

et al. 2019

Icarus

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Collisional charging is one potential initial step in generating lightning. In this work, we study the charging of colliding monodisperse, spherical basalt grains depending on ambient pressure. We used grains of 1.0 to 1.2 mm in one set and 2.0 to 2.4 mm in another set. We varied the ambient pressure between 0.03 mbar and 80 mbar. This especially includes Martian pressure being 6 mbar on average. At a few mbar the net charge gathering on colliding grains has a minimum. A smooth incline in charging occurs for larger pressures. Toward lower pressure the charge increases steeply. The pressure dependence is in agreement to a model where the maximum charge is limited by a gas discharge occurring between two charged colliding grains shortly after or before a collision. The capability of building up charge is at a minimum exactly in the range of Martian pressures. The charges on grains are at least a factor 5 smaller than at the highest pressure tested and still smaller compared to ambient pressure on Earth. This implies that on Mars collisional charging and the potential of subsequent generation of lightning or other large scale discharges are strongly reduced compared to Earth. This might result in less frequent and less energetic lightning on Mars.

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“…Note that some spectra were not retrieved when the brightness temperature of the incident radiation exceeded the detector temperature (i.e., during dust storm periods). The temperature profiles have been used to study the thermal structure over Olympus Mons [ Grassi et al , 2005a; Wolkenberg et al , 2010], the Hellas basin [ Grassi et al , 2007], and the south polar cap [ Giuranna et al , 2008].…”

Section: Data Setmentioning

confidence: 99%

Tidal variations in the Martian lower atmosphere inferred from Mars Express Planetary Fourier Spectrometer temperature data

Sato¹,

Fujiwara²,

Takahashi³

et al. 2011

Geophys. Res. Lett.

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We report on the characteristics of tidal variations in the Martian lower atmosphere (<45 km) using the Mars Express (MEX) Planetary Fourier Spectrometer (PFS) temperature data for about three Martian years (between the ends of MY26 and MY29). The PFS data, which widely cover local time, enable us to investigate diurnal variations in the atmospheric temperature at various altitudes. We focus on diurnal variations in the atmospheric temperature and on longitudinal temperature variability in a fixed local time frame. We find that the latitudinal and diurnal variations at 0.52 mbar (∼25 km) during the dust‐clear period (Ls = 30°–60°) are consistent with general characteristics presented by previous numerical simulations. The characteristics of the diurnal variations as a function of altitude in the tropics are also explained as results from the propagation of the migrating diurnal tide. The longitudinal temperature variability in the dayside (14.36–14.94 LT) equatorial regions (10°S–5°S) near the northern summer solstice (Ls= 76°–83°) in MY28 are investigated. The longitudinal temperature structure has two local maxima at 2.85 mbar (∼10 km) but is relatively uniform at 0.52 mbar. We find that the wave‐3 structure is apparent at 0.11 mbar (∼40 km) in the present case. This structure would be strongly dependent on activities of the atmospheric waves, e.g., the diurnal Kelvin wave 2 (DK2).

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The atmospheric temperatures over Olympus Mons on Mars: An atmospheric hot ring

Cited by 7 publications

References 23 publications

Dusty Deep Convection in the Mars Year 34 Planet‐Encircling Dust Event

Dusty Deep Convection in the Mars Year 34 Planet‐Encircling Dust Event

A challenge for martian lightning: Limits of collisional charging at low pressure

Tidal variations in the Martian lower atmosphere inferred from Mars Express Planetary Fourier Spectrometer temperature data

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