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

公众观众段落：许多改变人类居住景观的自然过程发生在很长的时间尺度上，这使得它们很难被观察到。例外情况包括在短时间内发生的地震、火山爆发和洪水等罕见的灾难性事件。许多影响我们居住的土地和景观的重要过程在人类无法察觉的时间尺度上运作。其中一个过程是沙子的风运输，对裸露的岩石表面和人造物体（包括建筑物、挡风玻璃、太阳能电池板和风力发电厂的涡轮机叶片）产生相关影响。该项目的目标是了解在南极干谷的长期风蚀过程，这是一个寒冷的沙漠环境，没有竞争过程（如雨水和植被）可以掩盖风蚀的影响。主要目标是恢复1983/1984年在南极干谷11个地点部署的岩石样本，同时对岩石样本进行测量并描述这些地点的特征。在20世纪80年代末和90年代初，一些样品被返回，表明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年后收集该实验中剩余的样本。现场工作将在2014/15年南方夏季进行。结果将允许直接测量磨损速率，从而测量砂输运的体积和时间尺度；这将结束对这类过程进行的最长时间的直接审查。在多沙和多风地区，可对建筑物、植被（作物）和人类存在的其他方面适当调整研究结果，以便更好地确定这些过程的影响，并可能减轻这些影响。该项目是一家小型企业马林空间科学系统公司（MSSS）和华盛顿大学（UW）之间的合作成果。科学与社会服务部将在其网站上突出这项南极研究，制作专题报告，描述我们的研究，并提供广泛的视觉材料。公众将通过网站上的每日更新和谷歌地球上准备的观看材料链接来参与。西澳大学的学生将参与实验室工作并解释结果。项目技术描述：该项目的目标是研究夹带颗粒在横贯南极山脉麦克默多干谷演化过程中的风蚀作用。在1983年至1984年的野外季节，在面向4个基本方向的10个地点的5个高度安装了5000多个岩石靶（另外一个地点包含较少的靶），以研究主要由风成磨损引起的物理风化速率。此外，在每个地点都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结果一致，但进一步强调，“平均”不应被解释为“均匀”。样品将使用0.01 mg精密天平进行质量测量，数字显微摄影来比较其表面特征和纹理的演变，扫描电子显微镜成像来检查磨损岩石表面的微观纹理，光学显微镜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1984-1994年测量的样品中，多达60-80%的磨损似乎发生在1984年的几个小时内。这与理论模型一致，认为磨损尺度是风速的五次方。实地工作将允许在三十年的暴露后返回多个样本，这将提供统计抽样（超出通过研究单个样本获得的数据），并将根据其他来源（例如LTER气象站）的互补环境和沙子动能通量数据产生质量损失数据。该研究有望提高对干谷（一个重要的冷沙漠环境）主要活动地貌过程之一的认识，并且坚实的经验数据库将提供自然条件下风成磨损的一般约束。

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.