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The rate of granule ripple movement on Earth and Mars |
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| Authors: | James R Zimbelman Rossman P Irwin III Fred Bunch Scott Stevens |
| Institution: | a Center for Earth and Planetary Studies, National Air and Space Museum MRC 315, Smithsonian Institution, Washington, DC 20013-7012, USA b Education Division, National Air and Space Museum MRC 305, Smithsonian Institution, Washington, DC 20013-7012, USA c Great Sand Dunes National Park and Preserve, 11500 Highway 150, Mosca, CO 81146-9798, USA d National Climatic Data Center, Federal Building, 151 Patton Ave., Asheville, NC 28801-5001, USA |
| Abstract: | The rate of movement for 3- and 10-cm-high granule ripples was documented in September of 2006 at Great Sand Dunes National Park and Preserve during a particularly strong wind event. Impact creep induced by saltating sand caused ∼24 granules min−1 to cross each cm of crest length during wind that averaged ∼9 m s−1 (at a height well above 1 m), which is substantially larger than the threshold for saltation of sand. Extension of this documented granule movement rate to Mars suggests that a 25-cm-high granule ripple should require from hundreds to thousands of Earth-years to move 1 cm under present atmospheric conditions. |
| Keywords: | Earth Geological processes Mars surface |
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