Eolian Compound Crescentic Dune (Draa) Dynamics

复合-复杂床型的沉积形成了风成岩记录的重要部分，但其气流和床型行为的实际动力学尚未得到解决。这显然妨碍了我们理解这些现代地层并解释它们的沉积。这里的工作构成了对这些特征的第一次详细研究。这项拟议工作的结果将是一项为期四年的研究，包括监测床状过程和迁移，加上地表气流和背风面气流宏观湍流结构的文件。这项研究代表了已经完成的、正在进行的和在此提出的研究的延续。地表过程和床型迁移将从空中映射到地面。风速计和微型叶片将被用来记录地表气流。气球和装有仪器的塔将被用来研究整个二次背风坡气流。这项研究的意义在于首次记录了大型复杂床型上的一次和二次气流的关系以及由此产生的床型响应。研究地点包括与南加州和内华达州接壤的阿尔戈多内斯沙丘区。研究的应用包括沙丘迁移、农田侵蚀/沉积、岸线沙丘过程以及古风成期特征和风况的解释。

Deposits of compound-complex bedforms form a significant portion of the eolian rock record, yet the actual dynamics of their airflow and bedform behavior have not been addressed. This obviously handicaps our ability to understand these modern bedforms and to interpret their deposit. Work here constitutes the first detailed study of these features. The results of this proposed work will be a four-year study consisting of monitoring bedform processes and migration, plus a documentation of surface airflow and of the structure of macro-turbulence of the lee-face airflow. This research represents a continuation of studies already completed, in progress, and proposed here. Surface processes and bedform migration will be mapped from the air on the ground. Anemometers and microvanes will be used to document surface airflow. Balloons and a tower with mounted instruments will be used to study the overall secondary lee- slope airflow. The significance of this study will be the first documentation of the relationship of primary and secondary airflow on a large complex bedform and the resulting bedform response. The study site includes the Algodones Dune Field bordering S. California and Nevada. Applications of the research include dune migration, erosion/deposition in farmland, shoreline dune processes, and interpretation of paleoeolian features and wind regimes.