Influence of dust on the dynamics of the martian atmosphere above the first scale height

Medvedev, Alexander S.; Kuroda, Takeshi; Hartogh, P.

doi:10.1016/j.aeolia.2011.05.001

Cited by 26 publications

(22 citation statements)

References 109 publications

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“…And if the MY 28 dust storm does have an obvious and/or long‐lasting influence, together with our results, it suggests that there exists a dust opacity threshold above which dust storms cause obvious and/or long‐lasting changes in the ionosphere, or even higher altitudes like 400 km, exists. Given the dust opacity values from Mars year 24 to 28 [e.g., Smith , ; Medvedev et al , ], this threshold might be roughly between a global‐averaged 9 μm dust optical depth, τ , of 0.5 and 1.0. In other words, as long as dust storms become large enough, above this threshold, they are able to affect the entire atmosphere to such an extent that the ionosphere and photoelectron fluxes are significantly affected.…”

Section: Discussionmentioning

confidence: 99%

“…Most of Mars' large dust storms occur in southern springs and summers, when Mars is near perihelion. Dust suspended in the dry Martian atmosphere is known to play an important role in the Martian atmospheric dynamics; when dust opacity is high enough, its absorption of solar radiation is comparable to CO 2 gas, thus contributing to the variability of the circulation and weather on Mars [e.g., Gierasch and Goody , ; Haberle et al , ; Medvedev et al , ].…”

Section: Introductionmentioning

confidence: 99%

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Mars photoelectron energy and pitch angle dependence on intense lower atmospheric dust storms

Liemohn

Mitchell

et al. 2014

J. Geophys. Res. Planets

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We have conducted a survey of the Mars Global Surveyor (MGS) electron data across all the pitch angles of 12 usable energy bins (11-746 eV) for dayside photoelectron observations over regions of strong crustal fields. Studies have shown that solar EUV flux is the main controlling factor, but dust storms play an important role as well. Our study of different energies and pitch angles has shown that the unusual bimodal solar flux dependence is not a common feature but mainly found in low energies and a few bins of higher-energy channels. By multiplying time-history dust opacity with a solar EUV proxy as a new controlling function, the statistically significant increase of the correlation of photoelectron flux against this function indicates that dust storms have a long-lasting influence on high-altitude photoelectron fluxes, especially at low energies and the pitch angle source regions of high-energy channels. The correlation increases experienced by the pitch angle source regions of all examined energy channels suggest that dust storms' influence most likely happens in the thermosphere-ionosphere source region of the photoelectrons, rather than at exospheric altitudes at or above MGS. Furthermore, by isolating the global-scale dust storm in Mars year 25 (2001) from the rest, the results suggest that this storm is entirely responsible for the second solar flux-dependent trend. While not excluding the possibility of this phenomenon being a one-time event, we hypothesize that there is a threshold of dust opacity at which the low-altitude dust's influence on high-altitude photoelectron fluxes begins to be significant.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mars photoelectron energy and pitch angle dependence on intense lower atmospheric dust storms

Liemohn

Mitchell

et al. 2014

J. Geophys. Res. Planets

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“…Such planet‐encircling storms do occasionally happen in the second half of the year, either at equinoxes, or around northern winter solstices as observed in 2007 during MY28 (e.g., Montabone et al., 2015). They dramatically impact the global circulation of the atmosphere (see the review of Medvedev et al., 2011c). To date, little is known about the influence of dust storms on GW generation, propagation, and associated effects in the middle and upper atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Gravity Wave Activity in the Atmosphere of Mars During the 2018 Global Dust Storm: Simulations With a High‐Resolution Model

2020

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Gravity waves (GWs) exist in atmospheres of all planets with convectively stable stratification. They transport energy and momentum from denser tropospheres to thinner upper levels (Yiğit & Medvedev, 2019). Effects produced by GWs are particularly strong in the middle and upper atmospheres of Earth and Mars (see recent reviews of Medvedev & Yiğit, 2019; Yiğit & Medvedev, 2015, correspondingly), thus making them a major dynamical mechanism that couples the lower and upper atmospheres on both planets. Being relatively small in size (from tens to hundreds of kilometers in horizontal wavelength) and short-lived (periods from a few minutes to several hours), GWs are thought to strongly affect the Martian global circulation. They close and even reverse zonal jets in the middle atmosphere (Barnes, 1990; Gilli et al., 2020; Medvedev et al., 2011a) and enhance the meridional circulation, which has implications for the meridional transport of tracers and important dynamical effects. The upwelling part of the meridional cell amplifies the transport of water into the thermosphere (Shaposhnikov et al., 2019), and the descending branch leads to thermospheric polar warmings (Bougher et al., 2006; Medvedev et al., 2011b). GW-induced downward transport Abstract Gravity wave (GW) activity in the lower and middle atmosphere of Mars during the global dust storm of 2018 has been studied for the first time using a high-resolution (GW-resolving) general circulation model. Dust storm simulations were compared with those utilizing the climatological distribution of dust in the absence of storms. Both scenarios are based on observations of the dust optical depth by the Mars Climate Sounder instrument on board the Mars Reconnaissance Orbiter. The modeling reveals a reduction of the wave activity by a factor of 2 or more in the lower atmosphere, which qualitatively agrees with recent observations. It is associated with a decline of GW generation due to baroclinic and convective stabilization of the Martian troposphere induced by the increased amount of airborne aerosols during the storm. Contrary to the decrease of GW activity in the lower atmosphere, wave energy and momentum fluxes in the middle atmosphere increase by approximately the same factor. This enhancement of GW activity is caused by the changes in the large-scale circulation, most importantly in the mean zonal wind, which facilitate vertical wave propagation by allowing for a greater portion of GW harmonics originated in the lower atmosphere to avoid filtering on their way to upper layers. Plain Language Summary Gravity waves (GWs) are oscillations of wind, temperature, pressure, and density that originate in the dense lower atmosphere. They grow in amplitude upon propagation upward and represent a major driving force in the thinner middle and upper atmosphere. GWs are difficult to account for in general circulation models because their scales are smaller than the resolution of the majority of such models. To circumvent this, we employ a high-resolution model that can explicitly ...

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“…Global‐scale effects of dust on Mars are numerous. Medvedev et al [] have recently presented a current review of dust storm effects in the lower and middle atmosphere. This paper addresses the less studied aspect of dust storms—their manifestation and consequences for the upper atmosphere.…”

Section: Introductionmentioning

confidence: 99%

General circulation modeling of the Martian upper atmosphere during global dust storms

et al. 2013

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Simulations with a general circulation model (GCM) have been performed to study the Martian upper atmosphere during two major dust storms. The GCM extending from the surface to about 160 km included a spectral parameterization of subgrid‐scale gravity waves suitable for planetary thermospheres, and prescribed four‐dimensional dust distributions corresponding to storm events near the equinox and solstice (Martian years 25 and 28, respectively). The results show that the wind and temperature fields in the upper atmosphere above ∼100 km respond to such storms as intensively as in the lower atmosphere. During the equinoctial storm, the temperature above the mesopause dropped by up to 30 K everywhere except in the Northern Hemisphere high latitudes, where it rose by up to 15 K. At the solstitial storm, the temperature above the mesopause decreased by up to 40 K in the winter hemisphere, by 15 K in the summer hemisphere, and increased by 30–40 K in tropics and in the summer hemisphere above 130 km. Prograde and retrograde zonal wind jets intensified throughout the atmosphere at all heights and during both dust scenarios. These changes are the result of the altered meridional overturning circulation induced by resolved and unresolved waves. Atmospheric density during dust storms enhanced in average by a factor of 2 to 3 in the mesosphere and lower thermosphere, which agrees well with observations.

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Influence of dust on the dynamics of the martian atmosphere above the first scale height

Cited by 26 publications

References 109 publications

Mars photoelectron energy and pitch angle dependence on intense lower atmospheric dust storms

Mars photoelectron energy and pitch angle dependence on intense lower atmospheric dust storms

Gravity Wave Activity in the Atmosphere of Mars During the 2018 Global Dust Storm: Simulations With a High‐Resolution Model

General circulation modeling of the Martian upper atmosphere during global dust storms

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