Short-term Unsteadiness in Aeolian Sediment Transport Across Beaches

Bernard O. Bauer，首席研究员（PI） Douglas J. Sherman，南加州大学洛杉矶分校（Co-PI），海滩风沙输运的短期不稳定性泥沙输运是地貌系统变化的基本动因。我们对沉积物输运过程的概念理解是健全的，但由于我们无法将理论转化为普遍适用的预测模型，这些知识的实际实施受到了限制。问题是由于技术和后勤障碍造成的。这项研究将加强我们对泥沙输运过程中不稳定的潜在作用的理解，以及通过关注风成海滩环境来参数化模型的适当手段。研究结果可作为其他地貌环境中运输过程的参考。将系统地研究秒到几十分钟时间尺度上的不稳定性，以确定风速波动是否对模拟海滩上的短期沉积物通量至关重要——现有的模型参数化运输是基于稳态假设。采用电子测力元件的连续测量、快速响应的沙阱将部署在现场，以提供风速和沉积物通量的同期时间序列。现场数据将提供对跨海滩输运率变异性特征的深入了解，并作为探索改进预测方程的基础。

SBR-9511529 Bernard O. Bauer, Principal Investigator (PI) Douglas J. Sherman, Co-PI University of Southern California, Los Angeles Short-Term Unsteadiness in Aeolian Sediment Transport Across Beaches Sediment transport is a fundamental agent of change in geomorphological systems. Our conceptual understanding of sediment transport processes is robust, but practical implementation of this knowledge is constrained by our inability to translate theory into generally-applicable predictive models. Problems occur as a result of technical and logistical hurdles. This research will enhance our understanding of the potential role of unsteadiness in sediment transport processes and the appropriate means of parameterizing models by focusing on an aeolian beach environment. The results should be indicative of transport processes in other geomorphic environments. Unsteadiness at temporal scales of seconds to tens of minutes will be investigated systematically to determine whether wind speed fluctuations are critical to modeling short-term sediment flux across beaches--existing model parameterizations of transport are based on steady-state assumptions. Continuously-measuring, fast-response sand traps employing electronic load cells will be deployed in the field to provide contemporaneous time series of both wind speed and sediment flux. The field data will provide insight into the character of transport rate variability across beaches and serve as a foundation for exploring improvements in predictive equations.