Aeolian megaripples, with 5‐ to 50‐m spacing, are abundant on the surface of Mars. These features were repeatedly targeted by high‐resolution orbital images, but they have never been observed to move. Thus, aeolian megaripples (especially the bright‐toned ones often referred as Transverse Aeolian Ridges—TARs) have been interpreted as relict features of a past climate. In this report, we show evidence for the migration of bright‐toned megaripples spaced 1 to 35 m (5 m on average) in two equatorial areas on Mars indicating that megaripples and small TARs can be active today. The moving megaripples display sand fluxes that are 2 orders of magnitudes lower than the surrounding dunes on average and, unlike similar bedforms on Earth, can migrate obliquely and longitudinally. In addition, the active megaripples in the two study areas of Syrtis Major and Mawrth Vallis show very similar flux distributions, echoing the similarities between dune crest fluxes in the two study areas and suggesting the existence of a relationship between dune and megaripple fluxes that can be explored elsewhere. Active megaripples, together with high‐sand flux dunes, represent a key indicator of strong winds at the surface of Mars. A past climate with a denser atmosphere is not necessary to explain their accumulation and migration.

中文翻译：

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火星上的巨波纹迁移


火星表面存在大量间距为 5 至 50 米的风积巨波纹。这些特征多次成为高分辨率轨道图像的目标，但从未观察到它们移动。因此，风积巨波纹（尤其是通常被称为横向风脊（TAR）的明亮色调的风积波纹）被解释为过去气候的残余特征。在本报告中，我们展示了火星两个赤道地区间隔 1 至 35 m（平均 5 m）的明亮色调巨型波纹迁移的证据，表明巨型波纹和小型 TAR 在今天可能很活跃。移动的巨型波纹显示出的沙通量平均比周围沙丘低两个数量级，并且与地球上类似的床型不同，它们可以倾斜和纵向迁移。此外，Syrtis Major 和 Mawrth Vallis 两个研究区域中的活跃巨波纹表现出非常相似的通量分布，这与两个研究区域沙丘顶部通量之间的相似性相呼应，并表明沙丘和巨波纹通量之间存在某种关系，可以通过在其他地方探索过。活跃的巨波纹和高沙流沙丘是火星表面强风的一个关键指标。过去大气层较稠密的气候不一定能解释它们的积累和迁移。