Wind‐related features in Gusev crater, Mars
Wind‐related features in Gusev crater, Mars
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火星古谢夫陨石坑中与风相关的特征
DOI：
10.1029/2002je002006
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发表时间：
2003
影响因子：
--
通讯作者：
R. Haberle
中科院分区：
文献类型：
--
作者：
R. Greeley;R. Kuzmin;S. Rafkin;T. Michaels;R. Haberle
[1]古谢夫陨石坑有着复杂的历史，从诺亚纪时期的一次撞击开始，以及随后的演变，包括与马阿迪姆山谷（Ma'adim Vallis）有关的侵蚀和沉积，马阿迪姆山谷从南部穿过古谢夫陨石坑。在火山口底部发现了各种与风有关的特征，包括沙丘模式、底形（如新月形沙丘）和可能反映风侵蚀的细长山丘。这些功能的方向与全球和大气模型的预测比较显示，风模式的季节和一天中的时间的函数。最强的全球风发生在秋末和初冬的东南方向，似乎是形成一个巨大的黑暗条纹的原因，它覆盖了100公里的陨石坑底部。在中等尺度上，明亮的风条纹与夜间从边缘和外围高地流入陨石坑的风有关;这些条纹被解释为在正大气静态稳定度期间从大气中沉降下来的尘埃沉积物。较小的特征包括各种黑色条纹和沙丘，其方向被推断为代表高风切变表面应力的局部区域。这些特征也往往与下午强烈的上坡风有关，这是由整个陨石坑的大气加热不均匀造成的。因此，大的深色条纹反映了全球范围的风模式，较小的深色特征和沙丘形状代表下午从火山口流出的强风，而小的明亮条纹代表与夜间流入火山口的风有关的尘埃沉积。模型预测的风况与风成特征的方向之间的相关性使人们相信模型基本上是正确的。由于古谢夫是包括火星探测漫游者在内的着陆器的主要候选着陆点，因此了解大气和表面的相互作用（包括风吹颗粒的侵蚀和沉积）对于评估这些任务的科学潜力非常重要。尽管古谢夫海底有丰富的风相关特征，但只有约1.2%的拟议着陆椭圆区域覆盖着有组织的底形（例如，沙丘），尽管沙尘的地幔也可能存在。根据对椭圆内随机着陆点的分析，对于95%的着陆点，到山脊、小陨石坑喷出物和其他潜在岩石源的横向距离在150米以内。
[1] Gusev crater has a complex history beginning with its formation by an impact in the Noachian Period and subsequent evolution, including erosion and deposition associated with Ma'adim Vallis, which cut through Gusev crater from the south. Various wind-related features are found on the crater floor, including albedo patterns, bedforms (such as barchan dunes), and elongated hills possibly reflecting erosion by the wind. Comparisons of the orientations of these features with predictions from global and atmospheric models show wind patterns as functions of season and time of day. Strongest global winds occur out of the southeast in the late fall and early winter and appear to be responsible for the formation of a large dark streak that drapes 100 km across the crater floor. On an intermediate-scale, bright wind streaks correlate with nighttime winds that flow into the crater from the rim and outlying high areas; these streaks are interpreted to be deposits of dust settled from the atmosphere during times of positive atmospheric static stability. Smaller features include various dark streaks and duneforms, the orientations of which are inferred to represent local zones of high wind-shear surface stress. These features also tend to correlate with strong afternoon upslope winds caused by the uneven heating of the atmosphere across the crater. Thus the large dark streak reflects global-scale wind patterns, the smaller dark features and duneforms represent flow of strong winds out of the crater in the afternoon, and the small bright streaks represent deposition of dust associated with nighttime flow of wind into the crater. The correlation between the wind regime predicted by the models and the orientations of the aeolian features gives confidence that the models are essentially correct. Because Gusev is a prime candidate landing site for landers, including the Mars Exploration Rovers, understanding the interplay of the atmosphere and the surface (including the erosion and deposition of windblown particles) is important in assessments of the science potential for these missions. Despite the abundance of wind-related features on the floor of Gusev, only about 1.2% of the proposed landing ellipse area is covered with organized bedforms (e.g., dunes), although mantles of sand and dust are also likely to be present. On the basis of an analysis of random landing points within the ellipse, traverse distances to ridges, ejecta from small craters, and other potential sources of rocks are within 150 m traverse distance for 95% of the touchdown points.