Role of Bedform Interactions and Boundary Conditions in Pattern Development

在空气或水下的波纹和沙丘等床形区域形成了地球、火星和其他行星上最引人注目的图案。这些模式是如何形成的在很大程度上是未知的。本研究试图通过检验模式自组织的假设来理解床型模式的发展。具体而言，研究探讨了底形本身在一组环境边界条件下的相互作用，作为对模式形成和演化的主要控制。边界条件，这是不同的每一个领域的底形，控制的频率和风格的相互作用，以产生模式是大致相似的，但在他们的细节是独特的，从字段到字段。这项研究将创建时间序列的高分辨率，三维数字地图，允许前所未有的文件的底形地形，底形之间的相互作用，并在一套代表性的环境，在其边界条件显着不同的模式演变。该项目使用（1）机载激光雷达探测新墨西哥州白色沙滩的风成沙丘，（2）低空航空摄影表征内布拉斯加州的北卢普河浅，（3）多波束声学勘测解决路易斯安那州南部的密西西比河深。此外，北卢普河内的实验将包括使用现场水槽来探索模式形成时对通道宽度的控制。这项研究的结果将提供必要的定量数据，以充分了解沙丘和沙丘场的不稳定，自组织行为的流体流动，沉积物侵蚀/沉积和表面地形之间的反馈的结果。沙丘和河流中的沙子的运输可以改变景观在大尺度和小尺度。 为该项目收集的数据将提高对地形如何因沙子运动而在时间和空间上发生变化的认识;这些过程主要控制着地球和其他行星上地形的演变。 为这一研究项目开发的方法和技术将促进对地球表面的实时监测，这是记录逐步环境变化所必需的，是成功管理自然资源所必需的信息。

Fields of bedforms such as ripples and dunes under air or water form some of the most striking patterns on Earth, Mars and other planets. How these patterns form is largely unknown. This research seeks to understand bedform-pattern development by testing the hypothesis that the patterns self-organize. Specifically, the research explores the interactions of the bedforms themselves within a set of environmental boundary conditions as the prinicpal control on the form and evolution of the patterns. The boundary conditions, which are different for every field of bedforms, control the frequency and style of interactions to yield patterns that are broadly similar, but are unique in their detail from field to field. This research will create time-series of high-resolution, three-dimensional digital maps that allow for unprecedented documentation of bedform topography, interactions among the bedforms, and pattern evolution across a representative suite of environments that differ significantly in their boundary conditions. This project uses (1) air-borne LiDAR to explore the aeolian dune field at White Sands, New Mexico, (2) low-altitude aerial photography to characterize the shallow North Loup River, Nebraska, and (3) multibeam acoustic surveys to resolve the deep Mississippi River, southern Louisiana. In addition, experimentation within the North Loup River will include using a field flume to explore the control of channel width upon pattern formation. Results of this study will provide the quantitative data necessary to fully understand the unsteady, self-organizing behavior of dunes and dune fields that arise as a consequence of the feedbacks between fluid flow, sediment erosion/deposition, and surface topography.The transport of sand in dunes and rivers can modify the landscape at both large and small scales. Data collected for this project will improve the knowledge of how topography changes in time and space as a result of sand movement; these are the proceses that primarily control the evolution of landforms on Earth and other planets. Methodologies and techniques developed for this research project will advance the real-time monitoring of Earth's surface that is necessary to document progressive environmental change, information that is vital for the successful management of natural resources.