Experimentally Derived Thresholds for Windblown Sand on Mars
Abstract Aeolian sand transport frequently occurs on Mars despite wind speeds rarely exceeding predicted thresholds for motion. This dissonance is problematic for understanding aeolian processes and the resulting geomorphologic responses in contemporary and ancient atmospheres. To address the appare...
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| Format: | Article |
| Language: | English |
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Wiley
2020-02-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2019GL084484 |
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| author | C. Swann D. J. Sherman R. C. Ewing |
| author_facet | C. Swann D. J. Sherman R. C. Ewing |
| author_sort | C. Swann |
| collection | DOAJ |
| description | Abstract Aeolian sand transport frequently occurs on Mars despite wind speeds rarely exceeding predicted thresholds for motion. This dissonance is problematic for understanding aeolian processes and the resulting geomorphologic responses in contemporary and ancient atmospheres. To address the apparent discrepancy between speeds required to initiate sand motion and transport observed from orbital and in situ observations, we conducted a series of wind tunnel experiments at Martian atmospheric pressures and used buoyancy as the similitude parameter to simulate the force required to initiate particle motion on Mars. Shear velocities were derived from velocity profiles corresponding to the onset of sporadic transport, which can induce downwind cascading motion. Here, we find that threshold shear velocities are slower than previously thought by a factor of 1.6 to 2.5. Measured wind speeds on Mars exceed our observed thresholds, thus offering one mechanism behind the dissonance between observations of transport below previous thresholds of motion. |
| format | Article |
| id | doaj-art-fa217a6abb7f4e1d9cf62c0d27e2e4cd |
| institution | Kabale University |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2020-02-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-fa217a6abb7f4e1d9cf62c0d27e2e4cd2025-08-20T03:49:32ZengWileyGeophysical Research Letters0094-82761944-80072020-02-01473n/an/a10.1029/2019GL084484Experimentally Derived Thresholds for Windblown Sand on MarsC. Swann0D. J. Sherman1R. C. Ewing2Sediment Dynamics Section, Seafloor Sciences Branch, Marine Geosciences Division U.S. Naval Research Laboratory Stennis Space Center MS USADepartment of Geography University of Alabama Tuscaloosa AL USADepartment of Geology and Geophysics Texas A&M University College Station TX USAAbstract Aeolian sand transport frequently occurs on Mars despite wind speeds rarely exceeding predicted thresholds for motion. This dissonance is problematic for understanding aeolian processes and the resulting geomorphologic responses in contemporary and ancient atmospheres. To address the apparent discrepancy between speeds required to initiate sand motion and transport observed from orbital and in situ observations, we conducted a series of wind tunnel experiments at Martian atmospheric pressures and used buoyancy as the similitude parameter to simulate the force required to initiate particle motion on Mars. Shear velocities were derived from velocity profiles corresponding to the onset of sporadic transport, which can induce downwind cascading motion. Here, we find that threshold shear velocities are slower than previously thought by a factor of 1.6 to 2.5. Measured wind speeds on Mars exceed our observed thresholds, thus offering one mechanism behind the dissonance between observations of transport below previous thresholds of motion.https://doi.org/10.1029/2019GL084484threshold of motionaeolian transportmarswind tunnelfluid thresholdcascading transport |
| spellingShingle | C. Swann D. J. Sherman R. C. Ewing Experimentally Derived Thresholds for Windblown Sand on Mars Geophysical Research Letters threshold of motion aeolian transport mars wind tunnel fluid threshold cascading transport |
| title | Experimentally Derived Thresholds for Windblown Sand on Mars |
| title_full | Experimentally Derived Thresholds for Windblown Sand on Mars |
| title_fullStr | Experimentally Derived Thresholds for Windblown Sand on Mars |
| title_full_unstemmed | Experimentally Derived Thresholds for Windblown Sand on Mars |
| title_short | Experimentally Derived Thresholds for Windblown Sand on Mars |
| title_sort | experimentally derived thresholds for windblown sand on mars |
| topic | threshold of motion aeolian transport mars wind tunnel fluid threshold cascading transport |
| url | https://doi.org/10.1029/2019GL084484 |
| work_keys_str_mv | AT cswann experimentallyderivedthresholdsforwindblownsandonmars AT djsherman experimentallyderivedthresholdsforwindblownsandonmars AT rcewing experimentallyderivedthresholdsforwindblownsandonmars |