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

面向公众的段落：许多改变人类居住景观的自然过程都是在很长的时间尺度上发生的，使得它们很难观察到。例外情况包括罕见的灾难性事件，如地震、火山喷发和短时间内发生的洪水。许多影响我们居住的土地和景观的重大过程都是在人类无法察觉的时间尺度上进行的。其中一个过程是沙子的风运，对裸露的岩石表面和人造物体产生相关影响，包括建筑物、挡风玻璃、太阳能电池板和风力发电机组叶片。该项目的目标是了解南极干旱山谷中长时间尺度的风蚀过程，这是一种寒冷的沙漠环境，没有可能掩盖影响的相互竞争的过程(如降雨和植被)。主要目标是找回1983/1984年部署在南极干燥山谷11个地点的岩石样本，以及对岩石样本的测量和地点的特征。在20世纪80年代末的S和90年代初的S，一些样本被送回，这表明需要更多的时间来积累关于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到31年后收集该实验的剩余样本。实地工作将在2014/15年度南澳夏季进行。结果将允许直接测量磨损率，从而测量沙子输送的体积和时间尺度；这将结束对此类过程进行的最长直接检查。为了更好地确定这些过程的影响和可能缓解的影响，可对建筑物、植被(作物)和多沙多风地区人类存在的其他方面进行适当的结果比例尺。该项目是小企业马林空间科学系统(MSSS)和华盛顿大学(UW)的合作成果。MSSS将在其网站上突出这项南极研究，开发描述我们研究的主题演示文稿，并提供广泛的可视材料。公众将通过网站上的每日更新和为在谷歌地球上查看而准备的材料的链接来参与。威斯康星大学的学生将参与实验室的工作和对结果的解释。项目的技术描述：该项目的目标是研究夹带粒子的风磨作用在横跨北极山脉的麦克默多干燥山谷的演变中所起的作用。在1983至1984年的野外季节，在10个地点(另有一个地点包含较少的目标)，在面向4个基本方向的5个高度安装了5000多个岩石靶材，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年后返回的样本进行的初步检查显示，当代的平均磨损率与宇宙成因同位素研究确定的一致，但进一步强调，不应将“平均”解释为“一致”的意思。这些样品将使用0.01毫克精密天平的质量测量、比较其表面特征和纹理演变的数字显微摄影、检查磨损岩石表面微观结构的扫描电子显微镜成像、以及少数样品薄片的光学显微镜来检查颗粒撞击延伸到磨损表面以下的后果。在1984-1994年间测量的样本中，多达60%-80%的磨损似乎发生在1984年的几个小时内。这与认为磨损尺度是风速的5次方的理论模型是一致的。实地工作将允许在暴露30年后返回多个样本，这将提供统计样本(超出通过研究单一样本获得的样本)，并将根据来自其他来源(例如LTER气象站)的补充环境和沙动能通量数据产生质量损失数据。这项研究有望促进对干旱山谷这一重要的寒冷沙漠环境中主要活跃地貌过程的深入了解，可靠的经验数据库将提供自然条件下风沙磨损的一般约束条件。

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.