Planetary Science Institute, Tucson, AZ 85719, USA.
Science. 2011 Feb 4;331(6017):575-8. doi: 10.1126/science.1197636.
Despite radically different environmental conditions, terrestrial and martian dunes bear a strong resemblance, indicating that the basic processes of saltation and grainfall (sand avalanching down the dune slipface) operate on both worlds. Here, we show that martian dunes are subject to an additional modification process not found on Earth: springtime sublimation of Mars' CO(2) seasonal polar caps. Numerous dunes in Mars' north polar region have experienced morphological changes within a Mars year, detected in images acquired by the High-Resolution Imaging Science Experiment on the Mars Reconnaissance Orbiter. Dunes show new alcoves, gullies, and dune apron extension. This is followed by remobilization of the fresh deposits by the wind, forming ripples and erasing gullies. The widespread nature of these rapid changes, and the pristine appearance of most dunes in the area, implicates active sand transport in the vast polar erg in Mars' current climate.
尽管环境条件截然不同，但地球和火星上的沙丘具有很强的相似性，这表明跳跃和谷物坠落（沙丘滑面下滑的沙雪崩）的基本过程在这两个星球上都存在。在这里，我们表明火星沙丘受到了一种在地球上找不到的额外的改造过程的影响：火星二氧化碳季节性极地冰盖的春季升华。火星北极地区的许多沙丘在火星年内在火星侦察轨道器上的高分辨率成像科学实验获取的图像中经历了形态变化。沙丘显示出新的壁龛、沟壑和沙丘围裙延伸。随后，风会重新移动新鲜的沉积物，形成波纹并抹去沟壑。这些快速变化的广泛性质，以及该地区大多数沙丘的原始外观，暗示了当前火星气候下广阔极地沙漠中活跃的沙运移。
