Collaborative Proposal: Decades-long Experiment on Wind-Driven Rock Abrasion in the Ice-Free Valleys, Antarctica

合作提案：南极洲无冰山谷中长达数十年的风驱动岩石磨损实验

• 批准号: 1341754
• 负责人: Michael Malin
• 金额: $ 19.4万
• 依托单位: Malin Space Science Systems Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-12-15 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1341754&HistoricalAwards=false
• 关键词: Collaborative; Proposal; Decades; long; Experiment

Paragraph for Public Audiences:Many of the natural processes that modify the landscape inhabited by humans occur over very long timescales, making them difficult to observe. Exceptions include rare catastrophic events such as earthquakes, volcanic eruptions, and floods that occur on short timescales. Many significant processes that affect the land and landscape that we inhabit operate on time scales imperceptible to humans. One of these processes is wind transport of sand, with related impacts to exposed rock surfaces and man-made objects, including buildings, windshields, solar panels and wind-farm turbine blades. The goal of this project is to gain an understanding of wind erosion processes over long timescales, in the Antarctic Dry Valleys, a cold desert environment where there were no competing processes (such as rain and vegetation) that might mask the effects. The main objective is recovery of rock samples that were deployed in 1983/1984 at 11 locations in the Antarctic Dry Valleys, along with measurements on the rock samples and characterization of the sites. In the late 1980's and early 1990's some of these samples were returned and indicated more time was needed to accumulate information about the timescales and impacts of the wind erosion processes. This project will allow collection of the remaining samples from this experiment after 30 to 31 years of exposure. The field work will be carried out during the 2014/15 Austral summer. The results will allow direct measurement of the abrasion rate and hence the volumes and timescales of sand transport; this will conclude the longest direct examination of such processes ever conducted. Appropriate scaling of the results may be applied to buildings, vegetation (crops), and other aspects of human presence in sandy and windy locations, in order to better determine the impact of these processes and possible mitigation of the impacts. The project is a collaborative effort between a small business, Malin Space Science Systems (MSSS), and the University of Washington (UW). MSSS will highlight this Antarctic research on its web site, by developing thematic presentations describing our research and providing a broad range of visual materials. The public will be engaged through daily updates on a website and through links to material prepared for viewing in Google Earth. UW students will be involved in the laboratory work and in the interpretation of the results.Technical Description of Project:The goal of this project is to study the role of wind abrasion by entrained particles in the evolution of the McMurdo Dry Valleys in the Transantarctic Mountains. During the 1983 to 1984 field seasons, over 5000 rock targets were installed at five heights facing the 4 cardinal directions at 10 locations (with an additional site containing fewer targets) to study rates of physical weathering due primarily to eolian abrasion. In addition, rock cubes and cylinders were deployed at each site to examine effects of chemical weathering. The initial examination of samples returned after 1, 5, and 10 years of exposure, showed average contemporary abrasion rates consistent with those determined by cosmogenic isotope studies, but further stress that "average" should not be interpreted as meaning "uniform." The samples will be characterized using mass measurements wtih 0.01 mg precision balances, digital microphotography to compare the evolution of their surface features and textures, SEM imaging to examine the micro textures of abraded rock surfaces, and optical microscopy of thin sections of a few samples to examine the consequences of particle impacts extending below the abraded surfaces. As much as 60-80% of the abrasion measured in samples from 1984-1994 appears to have occurred during a few brief hours in 1984. This is consistent with theoretical models that suggest abrasion scales as the 5th power of wind velocity. The field work will allow return of multiple samples after three decades of exposure, which will provide a statistical sampling (beyond what is acquired by studying a single sample), and will yield the mass loss data in light of complementary environmental and sand kinetic energy flux data from other sources (e.g. LTER meteorology stations). This study promises to improve insights into one of the principal active geomorphic process in the Dry Valleys, an important cold desert environment, and the solid empirical database will provide general constraints on eolian abrasion under natural conditions.

许多改变人类居住地景观的自然过程发生在很长的时间尺度上，使它们难以观察。 地震包括罕见的灾难性事件，如地震，火山爆发和洪水，发生在短时间内。许多影响我们居住的土地和景观的重要过程都在人类无法察觉的时间尺度上运作。其中一个过程是风沙的移动，对裸露的岩石表面和人造物体，包括建筑物、挡风玻璃、太阳能电池板和风电场涡轮机叶片产生相关影响。该项目的目标是了解南极干旱山谷长期的风蚀过程，这是一个寒冷的沙漠环境，没有可能掩盖影响的竞争过程（如雨水和植被）。 主要目的是回收1983/1984年在南极干旱河谷11个地点部署的岩石样品，沿着对岩石样品进行测量并确定地点的特征。在20世纪80年代末和90年代初，一些样本被送回，并表示需要更多的时间来积累有关风蚀过程的时间尺度和影响的信息。该项目将允许在暴露30至31年后收集该实验的剩余样本。 实地工作将在2014/15年南方夏季进行。 这些结果将允许直接测量磨损率，从而测量砂运输的体积和时间尺度;这将是有史以来对此类过程进行的最长的直接检查。 结果的适当缩放可应用于建筑物、植被（作物）以及桑迪和多风地区人类存在的其他方面，以便更好地确定这些过程的影响以及可能的影响缓解。该项目是一个小企业，马林空间科学系统（MSSS）和华盛顿大学（UW）之间的合作努力。海洋科学和社会科学部将在其网站上突出这一南极研究，编写专题介绍，介绍我们的研究，并提供广泛的视觉材料。公众将通过网站上的每日更新以及通过Google Earth中准备的查看材料的链接来参与其中。 华盛顿大学的学生将参与实验室工作和结果的解释。项目的技术说明：本项目的目标是研究在跨南极山脉的麦克默多干谷演变中夹带颗粒的风磨损作用。在1983年至1984年的野外季节，超过5000个岩石目标被安装在5个高度，面向4个主要方向，在10个地点（与一个额外的网站包含较少的目标），以研究物理风化率主要是由于风成磨损。此外，在每个地点部署了岩石立方体和圆柱体，以检查化学风化的影响。对暴露1年、5年和10年后返回的样品进行的初步检查显示，平均当代磨损率与宇宙成因同位素研究确定的磨损率一致，但进一步强调“平均”不应解释为“均匀”。“这些样品将通过以下方式进行表征：使用0.01毫克精密天平进行质量测量;数码显微摄影以比较其表面特征和纹理的演变;扫描电镜成像以检查磨损岩石表面的微观纹理;以及对一些样品的薄片进行光学显微镜检查，以检查颗粒影响延伸到磨损表面以下的后果。在1984年至1994年的样本中，多达60-80%的磨损似乎发生在1984年的短短几个小时内。这与理论模型相一致，该模型认为磨损尺度为风速的5次方。实地工作将允许在暴露30年后返回多个样本，这将提供统计抽样（超出通过研究单个样本所获得的数据），并将根据其他来源（例如LTER气象站）提供的补充环境和沙动能通量数据得出质量损失数据。这项研究有望提高对干旱河谷（一种重要的寒冷沙漠环境）主要活动地貌过程之一的了解，并且坚实的经验数据库将为自然条件下的风沙侵蚀提供一般限制。