Doctoral Dissertation Research: Spatial and Temporal Characteristics and Development Processes of Aeolian Sand Steamers

博士论文研究：风沙蒸船的时空特征及发展过程

• 批准号: 0002471
• 负责人: Douglas Sherman
• 金额: $ 1万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-01 至 2002-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0002471&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; Spatial; Temporal

Aeolian sand streamers, which also are known as sand snakes or windrows, are quasi-linear, streamwise concentrations of wind-blown sand. Streamers commonly are observed in natural aeolian sand-transport environments. Although these features have received minimal research attention, they can have significant consequences for the theoretical underpinnings and predictive powers of contemporary sand-transport models. Contemporary models treat aeolian sand transport as a uniform sheet of sand saltating over the bed surface. This description derives from fundamental assumptions regarding the uniformity and steadiness of the wind flow as well as assumptions regarding the homogeneity of the bed surface. The frequent occurrence of streamers in nature challenges these views and assumptions. The occurrence of streamers in aeolian environments may correspond with phenomena found in fluvial systems, leading some scientists to conclude that the spatial characteristics and temporal behavior of aeolian sand streamers should reflect theories and models of sediment transport in a variety of environments. This doctoral dissertation research project has three main objectives: (1) to quantify the shape and behavior of aeolian sand streamers, (2) to identify their origin, and (3) to determine their consequences for current aeolian transport models. These objectives will be addressed through the conduct of a set of field experiments at Oceano Dunes State Vehicle Recreation Area in central California. A variety of instruments, including cup-anemometers, hot-wire probes, saltiphones, Leatherman-type traps, and video imagery, will be deployed to measure the behavior and dimensions of streamers in conjunction with the wind-flow field and its characteristics. Sediment sampling and microsurveys will capture characteristics of the bed surface, such as micro-relief and moisture-content distribution. The integration and synthesis of experimental data will yield direct information regarding the spatial and temporal characteristics of aeolian sand streamers and will allow testing of the various hypotheses accounting for their origin. Comparison among the different types of data also will generate insights into how the presence of streamers under natural conditions affects contemporary transport models. This project aims to describe and measure a little-studied phenomenon that can have a potentially significant impact on current understandings of aeolian systems. In addition, the innovative research strategy and the use of this combination of instruments should shed a new light on issues of spatial and temporal variability and about the prediction of sediment transport in aeolian geomorphology. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.

风风胶流（也称为沙蛇或缠绕的）是准线性的，流式风吹的沙子的浓度。 在天然的风化砂环境环境中通常观察到流媒体。 尽管这些特征受到了最少的研究关注，但它们可能会对当代沙子传输模型的理论基础和预测能力产生重大影响。 当代模型将风化的沙子传输视为床表面上均匀的砂盐。该描述源自关于风流的统一性和稳定性以及关于床表面同质性的基本假设。 自然界中流媒体的频繁发生挑战了这些观点和假设。 风流环境中流媒体的发生可能与河流系统中的现象相对应，导致一些科学家得出结论，即风体砂流的空间特征和时间行为应反映在各种环境中的理论和沉积物传输的理论和模型。 该博士学位论文研究项目具有三个主要目标：（1）量化风水流媒体的形状和行为，（2）以识别其起源，以及（3）确定它们对当前的同性恋运输模型的后果。 这些目标将通过在加利福尼亚州中部的Oceano Dunes State State Recreation地区进行一系列实地实验来解决。 将部署各种仪器，包括杯形动画仪，热线探针，盐钳，皮革型陷阱和视频图像，以与风流场及其特征结合使用，以测量流媒体的行为和尺寸。 沉积物采样和微生成将捕获床表面的特征，例如微浮雕和水分含量分布。 实验数据的整合和综合将产生有关风流的空间和时间特征的直接信息，并将允许测试有关其起源的各种假设。 不同类型的数据之间的比较还将产生有关自然条件下流媒体的存在如何影响当代运输模型的见解。 该项目旨在描述和衡量一个有点研究的现象，这些现象可能会对当前对风化的风化系统的理解产生潜在的重要影响。 此外，创新的研究策略以及这种仪器组合的使用应该对空间和时间变异性问题以及对风险的预测在风化的地貌中的预测。 作为博士学位论文研究改进奖，该奖项还将提供支持，使有前途的学生能够建立强大的独立研究职业。