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.

风成沙流，也被称为沙蛇或风成沙，是风吹沙的准线性、顺流集中。 飘带是自然风沙环境中常见的现象。 虽然这些功能已收到最小的研究关注，他们可以有显着的影响，当代沙输运模型的理论基础和预测能力。 现代模式将风沙输送视为均匀的沙层在床面上跳跃。这种描述来自于关于风流均匀性和稳定性的基本假设以及关于床面均匀性的假设。 在自然界中频繁出现的飘带挑战了这些观点和假设。 在风成环境中出现的飘带可能与河流系统中发现的现象相对应，这使得一些科学家得出结论，风成沙飘带的空间特征和时间行为应反映各种环境中沉积物输运的理论和模型。 本博士论文研究项目有三个主要目标：（1）量化风成沙飘带的形状和行为，（2）确定其起源，（3）确定其对当前风成输运模型的影响。 这些目标将通过在加州中部的奥恰诺沙丘州立车辆娱乐区进行一系列实地实验来实现。 各种仪器，包括杯风速计，热线探头，saltiphones，莱瑟曼型陷阱，和视频图像，将被部署到测量的行为和尺寸的飘带结合风流场及其特性。 沉积物取样和微测量将捕捉河床表面的特征，如微地形和含水量分布。 实验数据的整合和综合将产生关于风成沙飘带的空间和时间特征的直接信息，并将允许测试解释其起源的各种假设。 不同类型的数据之间的比较也将产生对自然条件下拖缆的存在如何影响当代运输模型的见解。 该项目旨在描述和测量一种很少研究的现象，这种现象可能对目前对风成系统的理解产生潜在的重大影响。 此外，创新的研究战略和使用这一组合的工具应揭示了新的空间和时间变化的问题，并对预测沉积物的运输在风成地貌。 作为博士论文研究改进奖，该奖项还将提供支持，使有前途的学生建立一个强大的独立的研究生涯。