Major dust storms and westward traveling waves on Mars

Wang, Huiqun

doi:10.1002/2017gl072894

Cited by 12 publications

(14 citation statements)

References 29 publications

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“…It should be noted that despite the narrowness of the peaks of the 8 < P ≤ 60 sol eddies in Fig. 2a&c, these results are consistent with Wang (2017) because the vertical integration in the KE calculation and the non-linear relationship between KE and the eddy winds sharpens the changes in KE versus the signatures in temperature observations. Murphy et al (1995) also found a slowly propagating westward wave in their global dust storm simulation and suggested that the westward wave signals polar warming.…”

Section: Evolution Of Globally Averaged Eddy Kinetic Energysupporting

confidence: 78%

“…Thus, the 8 < P ≤ 60 sol eddies are closely related to mature, large dust storms and not all dust storm sequences. Wang (2017) found that westward traveling waves are among the signatures of major dust storms on Mars. Those traveling waves are characterized by wave periods longer than about 15 sols and are included in the 8 < P ≤ 60 sol eddies shown in Fig.…”

Section: Evolution Of Globally Averaged Eddy Kinetic Energymentioning

confidence: 99%

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Eddy evolution during large dust storms

Battalio

Wang

2020

Icarus

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The evolution of eddy kinetic energy during the development of large regional dust storms on Mars is investigated using the Mars Analysis Correction Data Assimilation (MACDA) reanalysis product and the dust storm data derived from Mars Global Surveyor Mars Daily Global Maps. Transient eddies in MACDA are decomposed into different components according to their eddy periods: P ≤ 1 sol, 1 < P ≤ 8 sols, 8 < P ≤ 60 sols. This paper primarily focuses on the Mars year 24 pre-solstice "A" storm that starts with many episodes of frontal/flushing dust storms from the northern hemisphere and attains its maximum global mean opacity after dust expansion in the southern hemisphere. During the development of this storm, the dominant eddies in terms of eddy kinetic energy progress from the 1 < P ≤ 8 sol eddies in the northern mid/high latitudes to the P ≤ 1 sol eddies (dominated by thermal tides) in the southern mid latitudes, and the 8 < P ≤ 60 sol eddies show a prominent peak with the increased global-mean dust opacity. The peaks of the 1 < P ≤ 8 sol eddies are found to best correlate with the average area of textured frontal/flushing dust storms within 40 • N -60 • N. The region where the 1 < P ≤ 8 sol eddies increase the most corresponds to the main flushing channel. The eddy kinetic energy of the P ≤ 1 eddies, dominated by P = 1 and its harmonics, increases with the global mean dust opacity both before and after the winter solstice in Mars year 24. The 8 < P ≤ 60 sol eddies briefly spike during large, regional dust storms but remain weak if dust storm sequences do not lead to a major dust storm. Zonal wavenumber analysis of eddy kinetic energy shows that the peaks of the 1 < P ≤ 8 eddies often result from combinations of zonal wavenumbers 1 to 3, while the P ≤ 1 eddies and 8 < P ≤ 60 sol eddies are each dominated by zonal wavenumber 1.

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Section: Evolution Of Globally Averaged Eddy Kinetic Energysupporting

confidence: 78%

Section: Evolution Of Globally Averaged Eddy Kinetic Energymentioning

confidence: 99%

Eddy evolution during large dust storms

Battalio

Wang

2020

Icarus

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“…Nevertheless, these steady‐state model results do provide some general climatological insights into why some tidal components are likely candidates to explain the MO and MRO longitudinal structures during certain seasons, and why other tides are not. Throughout both MO and MRO aerobraking missions, phases of k s =1 and k s =2 are characterized by zonal migrations with periods between 15 and 45 sols; clean eastward migrations for MO but both eastward and westward migrations occur for MRO. A rudimentary analysis demonstrates that these migrations plausibly arise from modulations of D0, S0, and DE1 by slow waves in the lower atmosphere that have been reported in the literature (Banfield et al, ; L. Wang, ; Wilson et al, ). At low to middle latitudes k s =3 and k s =4 density variations (±15%) occur at about half the amplitudes of k s =1 and k s =2 (±30%). MO and MRO amplitudes and phases at latitudes between 20° and 45° latitude are in good agreement and are attributable to DE2 and DE3, respectively.…”

Section: Discussionmentioning

confidence: 70%

“…Moreover, they are characterized by significant hemispheric asymmetries and interannual variability in terms of wave periods and amplitudes. Dust storm onset during NH winter can alter the slow wave behavior, in particular, trigger the switchover from eastward to westward traveling slow waves (Banfield et al, ; H. Wang, ; Wilson et al, ).…”

Section: Resultsmentioning

confidence: 99%

Polar Region Variability in the Lower Thermosphere of Mars From Odyssey and Reconnaissance Orbiter Aerobraking Measurements

Forbes

Zhang

2018

JGR Space Physics

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Accelerometer measurements of lower-thermosphere densities during the aerobraking phases of Mars Odyssey (MO) and Mars Reconnaissance Orbiter (MRO) are analyzed to reveal new perspectives on the longitudinal, latitudinal, local time, and temporal variability of Mars atmosphere. The MO and MRO accelerometers sample the atmosphere similarly, making for interesting comparisons and insights. Periapsis measurements began near 70 ∘ N (MO) and 70 ∘ S (MRO) latitude, respectively, near winter solstices; slowly approached the poles at near-constant 1730-2000 hr local times (LT); underwent nearly 8-hr shifts in LT near the poles; and then descended in latitude to about 20 ∘ N and 20 ∘ S near 0330 hr LT.In contrast with most prior studies of Mars thermosphere, emphasis here is placed on the space-based k s = 1 (wave-1) and k s = 2 (wave-2) components of the longitudinal density structures in the polar regions (≥70 ∘ ). Expressed in terms of percent with respect to the zonal mean, k s = 1 amplitudes are dominant with mission mean amplitudes of 22%(18.5%) for MO(MRO), and likely arise from the zonally symmetric diurnal tide (D0) and/or a stationary planetary wave with zonal wave number s = 1 (SPW1). Mission-mean k s = 2 amplitudes are 17.6%(13.6%) for MO(MRO) and are interpreted as arising from the zonally symmetric semidiurnal tide (S0) and the eastward propagating diurnal tide with s = −1 (DE1). Phases of k s = 1 and k s = 2 are characterized by zonal migrations with periods between 15 and 45 sols; these features are interpreted in terms of modulations of D0, S0, and DE1 by slow waves in the lower atmosphere that have been reported in the literature.

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“…To understand the results in section 3.1, this study examines the dominant wave mode of 1.2 < P ≤ 20 sols eastward traveling waves on both σ levels. Although westward traveling waves are present during major dust storms, they are mostly filtered out in this study due to their long wave periods (Banfield et al, ; Wang, ). Figures and show the results derived from the T and V fields, respectively.…”

Section: Resultsmentioning

confidence: 99%

Cross‐Equatorial Flushing Dust Storms and Northern Hemisphere Transient Eddies: An Analysis for Mars Year 24

Wang

2018

JGR Planets

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The relationship between frontal/flushing dust storms and northern hemisphere synoptic period transient eddies in Mars year 24 is examined in this paper. Frontal dust storms are observed roughly continuously during the presolstice (early/middle fall) and postsolstice (middle/late winter) time periods, but flushing dust storms that cross the equator are confined to shorter seasonal windows on both sides of the solsticial pause. In the lower atmosphere, the timing of cross‐equatorial flushing dust storms correlates better with eddy temperature than with eddy meridional wind; in the middle atmosphere, it correlates better with eddy meridional wind than with eddy temperature. This is because both the lower atmosphere eddy temperature and the middle atmosphere eddy meridional wind are dominated by zonal wave number m = 3 eastward traveling waves during the cross‐equatorial flushing dust storm periods. Frontal dust storms do not seem to be limited to any particular wave mode, but cross‐equatorial flushing dust storms appear to be closely related to m = 3 eastward traveling waves, at least in Mars year 24. The effectiveness of m = 3 waves in this regard is partially due to their amplitudes but more importantly due to their seasonal distributions and latitudinal positions. During the time periods when m = 3 waves are strong, the m = 3 waves are also located at lower latitudes, closer in distance to the fairly strong southward mean meridional wind in the low latitudes. Dust in frontal dust storms at high latitudes can be easily entrained into the low‐latitude circulation and be efficiently transported southward.

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Major dust storms and westward traveling waves on Mars

Cited by 12 publications

References 29 publications

Eddy evolution during large dust storms

Eddy evolution during large dust storms

Polar Region Variability in the Lower Thermosphere of Mars From Odyssey and Reconnaissance Orbiter Aerobraking Measurements

Cross‐Equatorial Flushing Dust Storms and Northern Hemisphere Transient Eddies: An Analysis for Mars Year 24

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