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The morphology and dynamics of these ripples, intermediate\u2010scale bedforms (termed megaripples and Transverse Aeolian Ridges [TARs]), and sand dunes reflect information regarding regional boundary conditions. We found that populations of polar megaripples and larger TARs are distinct in terms of their morphology, spatial distribution, and mobility. Whereas regionally restricted TARs appeared degraded and static in long\u2010baseline observations, polar megaripples were not only widespread but migrating at relatively high rates (0.13\u00a0\u00b1\u00a00.03\u00a0m\/Earth year) and possibly more active than other regions on Mars. This high level of activity is somewhat surprising since there is limited seasonality for aeolian transport due to surficial frost and ice during the latter half of the martian year. A comprehensive analysis of an Olympia Cavi dune field estimated that the advancement of megaripples, ripples, and dunes avalanches accounted for \u223c1%, \u223c10%, and \u223c100%, respectively, of the total aeolian system's sand fluxes. This included dark\u2010toned ripples that migrated the average equivalent of 9.6\u00a0\u00b1\u00a06\u00a0m\/yr over just 22\u00a0days in northern summer\u2014unprecedented rates for Mars. While bedform transport rates are some of the highest yet reported on Mars, the sand flux contribution between the different bedforms does not substantially vary from equatorial sites with lower rates. Seasonal off\u2010cap sublimation winds and summer\u2010time polar storms are attributed as the cause for the elevated activity, rather than cryospheric processes.<\/jats:p>","DOI":"10.1029\/2021je006970","type":"journal-article","created":{"date-parts":[[2021,11,13]],"date-time":"2021-11-13T02:54:16Z","timestamp":1636772056000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":25,"title":["Widespread Megaripple Activity Across the North Polar Ergs of Mars"],"prefix":"10.1029","volume":"126","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8497-8994","authenticated-orcid":false,"given":"Matthew","family":"Chojnacki","sequence":"first","affiliation":[{"name":"Planetary Science Institute  Lakewood CO USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3583-2267","authenticated-orcid":false,"given":"David A.","family":"Vaz","sequence":"additional","affiliation":[{"name":"Centre for Earth and Space Research of the University of Coimbra Observat\u00f3rio Geof\u00edsico e Astron\u00f3mico da Universidade de Coimbra  Coimbra Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3196-6620","authenticated-orcid":false,"given":"Simone","family":"Silvestro","sequence":"additional","affiliation":[{"name":"SETI Institute Carl Sagan Center  Mountain View CA USA"},{"name":"INAF Osservatorio Astronomico di Capodimonte  Napoli Italia"}]},{"given":"David C. A.","family":"Silva","sequence":"additional","affiliation":[{"name":"Centre for Earth and Space Research of the University of Coimbra Observat\u00f3rio Geof\u00edsico e Astron\u00f3mico da Universidade de Coimbra  Coimbra Portugal"}]}],"member":"13","published-online":{"date-parts":[[2021,11,24]]},"reference":[{"key":"e_1_2_9_1_2_1","first-page":"265","volume-title":"The physics of blown sand and desert dunes","author":"Bagnold R. 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