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

风成沙流带，也被称为沙蛇或沙窗，是准线性的，风吹沙的流向集中。通常在自然风沙运输环境中观察到飘带。尽管这些特征得到的研究关注很少，但它们可能对当代沙质输运模型的理论基础和预测能力产生重大影响。当代的模型把风沙输运看作是均匀的沙粒在床面上跳跃。这种描述来源于关于气流均匀性和稳定性的基本假设，以及关于床面均匀性的基本假设。自然界中频繁出现的飘带挑战了这些观点和假设。风成环境中的流沙的出现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，风成沙流沙的空间特征和时间行为应该反映出各种环境中泥沙输运的理论和模型。本博士论文研究项目有三个主要目标：(1)量化风成沙流的形状和行为；(2)确定其起源；(3)确定其对当前风成沙输运模式的影响。这些目标将通过在加利福尼亚州中部的Oceano Dunes州立车辆游乐区进行的一系列实地实验来实现。将部署各种仪器，包括杯式风速计、热线探头、电话、莱瑟曼式陷阱和视频图像，以测量与风流场及其特征相关的飘带的行为和尺寸。沉积物取样和微观调查将捕捉床面特征，如微起伏和水分含量分布。综合和综合实验数据将产生关于风成沙流的空间和时间特征的直接资料，并将允许检验关于其起源的各种假设。通过对不同类型数据的比较，还可以深入了解在自然条件下，飘带的存在如何影响当代的运输模式。该项目旨在描述和测量一种很少被研究的现象，这种现象可能对当前对风成系统的理解产生潜在的重大影响。此外，创新的研究策略和这种仪器组合的使用应有助于对时空变异问题和风沙地貌中沉积物输运的预测提供新的认识。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研究生涯。

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.