Dust Devil Formation

Rafkin, Scot; Jemmett-Smith, Bradley; Fenton, L. K.; Lorenz, Ralph D.; Takemi, Tetsuya; Ito, Junshi; Tyler, D.

doi:10.1007/s11214-016-0307-7

Cited by 41 publications

(40 citation statements)

References 77 publications

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“…Previous studies suggest that light background winds are beneficial to dust devil formation in numerical models (e.g., Raasch & Franke, ) and in the real atmosphere (e.g., Rafkin et al, ). A further increase in background wind, however, turns the convective cells to a band‐like pattern, therefore, inhibiting the formation of dust devils (Raasch & Franke, ; Sinclair, ).…”

Section: Resultsmentioning

confidence: 97%

Toward Large‐Eddy Simulations of Dust Devils of Observed Intensity: Effects of Grid Spacing, Background Wind, and Surface Heterogeneities

et al. 2019

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Dust devils are convective vortices with a vertical axis of rotation made visible by lifted soil particles. Currently, there is great uncertainty about the extent to which dust devils contribute to the atmospheric aerosol input and thereby influence Earth's radiation budget. Past efforts to quantify the aerosol transport and study their formation, maintenance, and statistics using large‐eddy simulation (LES) have been of limited success. Therefore, some important features of dust devil‐like vortices simulated with LES still do not compare well with those of observed ones. One major difference is the simulated value of the core pressure drop, which is almost 1 order of magnitude smaller compared to the observed range of 250 to 450 Pa. However, most of the existing numerical simulations are based on highly idealized setups and coarse grid spacings. In this study, we investigate the effects of various factors on the simulated vortex strength with high‐resolution LES. For the fist time, we are able to reproduce observed core pressures by using a high spatial resolution of 2 m, a model setup with moderate background wind and a spatially heterogeneous surface heat flux. It is found that vortices mainly appear at the lines of horizontal flow convergence above the centers of the strongly heated patches, which is in contrast to some older observations in which vortices seemed to be created along the patch edges.

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Section: Resultsmentioning

confidence: 97%

Toward Large‐Eddy Simulations of Dust Devils of Observed Intensity: Effects of Grid Spacing, Background Wind, and Surface Heterogeneities

et al. 2019

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“…In order to initiate a convective vortex, there must be sufficient convective energy in the boundary layer to overcome the boundary layer turbulence. Field work and theoretical analyses suggest the following criterion for dust devil formation (Rafkin et al, 2016):…”

Section: Properties Of Dust Devils On Titanmentioning

confidence: 99%

“…where h is the boundary layer depth and L is the Obukhov length (Obukhov, 1971). In this context, the Obukhov length is the height above the ground at which production of turbulence by shear and buoyancy are equal, and a small negative value may imply buoyant conditions (Rafkin et al, 2016). Based on the data returned by the Huygens lander (Tokano et al, 2006), L was calculated as −0.32 m, giving −h∕L ≈ 1, 000 for h = 440 m. Inequality (2) suggests a lower limit on ΔT∕T required to form dust devils.…”

Section: Properties Of Dust Devils On Titanmentioning

confidence: 99%

“…However, some conditions on Titan may impede dust devil production. The ambient wind field is probably the source for dust devil vorticity, requiring some minimum ambient wind speed; field studies (Rafkin et al, 2016) suggest 1 m s −1 . Whether the same threshold applies to Titan should be the subject of future work, but measured surface wind speeds (Bird et al, 2005) are ≤ 1 m s −1 , while results from (Tokano, 2010) and (Lora et al, 2015) suggest typical speeds below 0.5 m s −1 at low latitudes.…”

Section: Properties Of Dust Devils On Titanmentioning

confidence: 99%

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Dust Devils on Titan

et al. 2020

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Conditions on Saturn's moon Titan suggest that dust devils, which are convective, dust‐laden plumes, may be active. Although the exact nature of dust on Titan is unclear, previous observations confirm an active aeolian cycle, and dust devils may play an important role in Titan's aeolian cycle, possibly contributing to regional transport of dust and even production of sand grains. The Dragonfly mission to Titan will document dust devil and convective vortex activity and thereby provide a new window into these features, and our analysis shows that associated winds are likely to be modest and pose no hazard to the mission.

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“…DDs effectively transport dust in the form of a suspension upwards, where it is picked up by regional winds and carried for several hours or days over long distances. Fine African dust can be transported to the South of Europe and reaches the Caribbean and southeastern United States each summer [27,[87][88][89] with concentrations typically in the range of 10 to 100 µg/m 3 . This is between one third and one half of the observed dust particles with a diameter of less than 2.5 µm.…”

Section: The Dustiness Of the Atmosphere And Climatementioning

confidence: 99%

Dust Devils: Structural Features, Dynamics and Climate Impact

Onishchenko

Fedun

Horton

et al. 2019

Climate

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According to modern concepts, the main natural sources of dust in the atmosphere are dust storms and associated dust devils—rotating columns of rising dust. The impact of dust and aerosols on climate change in the past, present and future is one of the poorly understood and, at the same time, one of the fundamental elements needed for weather and climate forecasting. The purpose of this review is to describe and summarise the results of the study of dust devils in the Earth’s atmosphere. Special attention is given to the description of the 3D structures, the external flows and atmospheric gradients of temperature that lead to the generation and maintenance of the dust devils.

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Dust Devil Formation

Cited by 41 publications

References 77 publications

Toward Large‐Eddy Simulations of Dust Devils of Observed Intensity: Effects of Grid Spacing, Background Wind, and Surface Heterogeneities

Toward Large‐Eddy Simulations of Dust Devils of Observed Intensity: Effects of Grid Spacing, Background Wind, and Surface Heterogeneities

Dust Devils on Titan

Dust Devils: Structural Features, Dynamics and Climate Impact

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