Dust devil vortices seen by the Mars Pathfinder Camera

Metzger, S. M.; Carr, James R.; Johnson, J. R.; Parker, T. J.; Lemmon, M. T.

doi:10.1029/1999gl008341

Cited by 162 publications

(156 citation statements)

References 16 publications

(8 reference statements)

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“…Results in Table 4 images [Metzger et al, 1999], and these vortices probably also were associated with rapid, localized changes in wind direction. For these reasons we postpone averaging until later in the data reduction process and report 0 in Table 4 without the effect of aligning deflections along averaged (b, in case some variations of qb within individual S0173 activations are significant.…”

Section: Conversion Of Raw Image Measurements Inmentioning

confidence: 99%

Results of the Imager for Mars Pathfinder windsock experiment

Sullivan¹,

Greeley²,

Kraft³

et al. 2000

J. Geophys. Res.

102

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Abstract. The Imager for Mars Pathfinder (IMP) windsock experiment measured wind speeds at three heights within 1.2 m of the Martian surface during Pathfinder landed operations. These wind data allowed direct measurement of near-surface wind profiles on Mars for the first time, including determination of aerodynamic roughness length and wind friction speeds. Winds were light during periods of windsock imaging, but data from the strongest breezes indicate aerodynamic roughness length of 3 cm at the landing site, with wind friction speeds reaching 1 m/s. Maximum wind friction speeds were about half of the threshold-of-motion friction speeds predicted for loose, fine-grained materials on smooth Martian terrain and about one third of the threshold-of-motion friction speeds predicted for the same size particles over terrain with aerodynamic roughness of 3 cm. Consistent with this, and suggesting that low wind speeds prevailed when the windsock array was not imaged and/or no particles were available for aeolian transport, no windrelated changes to the surface during mission operations have been recognized. The aerodynamic roughness length reported here implies that proposed deflation of fine particles around the landing site, or activation of duneforms seen by IMP and Sojourner, would require wind speeds >28 m/s at the Pathfinder top windsock height (or >31 m/s at the equivalent Viking wind sensor height of 1.6 m) and wind speeds >45 m/s above 10 m. These wind speeds would cause rock abrasion if a supply of durable particles were available for saltation. Previous analyses indicate that the Pathfinder landing site probably is rockier and rougher than many other plains units on Mars, so aerodynamic roughness length elsewhere probably is less than the 3-cm value reported for the Pathfinder site.

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Section: Conversion Of Raw Image Measurements Inmentioning

confidence: 99%

Results of the Imager for Mars Pathfinder windsock experiment

Sullivan¹,

Greeley²,

Kraft³

et al. 2000

J. Geophys. Res.

102

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“…For Mars, Metzger et al (1999) used column opacity to estimate the particle loading for a dust devil observed by the Imager for Mars Pathfinder camera. They Renno et al, 1998 andRenno et al, 2000) and the dust load estimate of Metzger et al, (1999) to estimate a flux of 70 mg m -2 s -1 .…”

Section: Comparisonmentioning

confidence: 99%

“…More attempts have been made to estimate dust load for martian dust devils using estimates of optical depth from orbit (Thomas and Gierasch, 1985) and the surface Greeley et al, 2006;Greeley et al, 2010). Thomas and Gierasch (1985) measured a dust load of ~ 30 mg m -3 ; Metzger et al (1999) found a range from 10 to 100 g m -3 . Greeley et al (2006) published data only for estimated flux and again particle loads cannot be estimated from their data without attempting to back-calculate particle loads based on cited average vertical wind speeds and flux data.…”

Section: Introductionmentioning

confidence: 99%

In situ measurements of particle load and transport in dust devils

Metzger

Balme

Towner

et al. 2011

Icarus

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“…[4] Tracks left by the passage of dust devils are found on nearly every region across the Martian surface [Cantor and Edgett, 2002], and nearly every orbiter and lander sent from Earth has directly observed active plumes, including: Viking Landers 1 & 2 (passage of vortex cores inferred by meteorological data) [Ringrose et al, 2003], Viking Orbiters 1 & 2 [Thomas and Gierasch, 1985], Mars Pathfinder Lander [Schofield et al, 1997;Metzger et al, 1999] and Mars Global Surveyor (MGS) [Edgett and Malin, 2000]. Measured diameters were between 28-509 m, with heights of 170 -8500 m. An extensive survey using 2 p.m. Mars Orbiter Camera (MOC) wide and narrow-angle images was conducted by Fisher et al [2005], who determined that Martian dust devils exhibit some regional and seasonal dependence with a bias toward northern latitudes during the warmest seasons.…”

Section: Introductionmentioning

confidence: 99%

THEMIS VIS and IR observations of a high‐altitude Martian dust devil

Cushing

Titus

Christensen

2005

Geophysical Research Letters

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The Mars Odyssey Thermal Emission Imaging System (THEMIS) imaged a Martian dust devil in both visible and thermal‐infrared wavelengths on January 30, 2004. We believe this is the first documented infrared observation of an extraterrestrial dust devil, and the highest to be directly observed at more than 16 kilometers above the equatorial geoid of Mars. This dust devil measured over 700 meters in height and 375 meters across, and the strongest infrared signature was given by atmospheric dust absorption in the 9‐micron range (THEMIS IR band 5). In addition to having formed in the extremely low‐pressure environment of about 1 millibar, this dust devil is of particular interest because it was observed at 16:06 local time. This is an unusually late time of day to find dust devils on Mars, during a period when rapid surface cooling typically reduces the boundary‐layer turbulence necessary to form these convective vortices. Understanding the mechanisms for dust‐devil formation under such extreme circumstances will help to constrain theories of atmospheric dynamics, and of dust lifting and transport mechanisms on Mars.

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Dust devil vortices seen by the Mars Pathfinder Camera

Abstract: Abstract. Discovery of dust devil vortices in Mars

Cited by 162 publications

References 16 publications

Results of the Imager for Mars Pathfinder windsock experiment

Results of the Imager for Mars Pathfinder windsock experiment

In situ measurements of particle load and transport in dust devils

THEMIS VIS and IR observations of a high‐altitude Martian dust devil

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