An Integrated Modeling and Experimental Study of the Formation and Dynamics of Patterned Ground

图案地面形成和动力学的综合建模和实验研究

• 批准号: 9530809
• 负责人: Bernard Hallet
• 金额: $ 26.61万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-06-01 至 2000-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9530809&HistoricalAwards=false
• 关键词: Integrated; Modeling; Experimental; Study; Formation

The emergence of order from disorder is observed in a wide range of complex dynamical systems. Several geological features, including patterned ground, constitute some of the clearest and most accessible examples of abiotic self-organization in nature. It is proposed to investigate the spontaneous emergence and dynamics of patterned ground through a coordinated program of field measurement and computer simulation of discrete particle motion in soil subjected to freeze/thaw activity. The close bending of these two approaches promises to be synergistic, with the simulations guiding the investigations in formulating novel and more precise questions in the filed and vice-versa. A new and more fundamental view of patterned ground as a prime example of self-organization will be obtained through the integration of the following specific objectives: (1) to develop a three-dimensional computer simulation of discrete particle motion in soil subjected to recurrent freezing and thawing, and use it to investigate the development of patterns in frozen ground; (2) to measure stone and soil displacements, document the formation of patterns and their reaction to disturbances, and monitor with automated instrumentation soil temperature, moisture and climate parameters in established study sites with well developed sorted circles and stripes; (3) to construct a micro-mechanical model of sorting in patterned ground through computer simulation and laboratory experimentation; and (4) to develop a realistic heat and mass transfer model to investigate factors critical in the formation of sorted circles: active layer depth and three-dimensional geometry of propagating freezing and thawing fronts. An important practical benefit of developing a realistic near-surface heat transfer model for frozen ground is that it promises to contribute to a more precise understanding of both the anticipated impacts of climate change permafrost areas, and the record of recent climate change that is contained in permafrost temperatures. The goal of the proposed research is to understand the processes through which patterns such as these circles of stones in the Arctic arise from a disordered initial state: in this case, a wave cut platform covered with 1-2 m of assorted beach sediments.

在各种复杂的动力系统中都可以观察到从无序到有序的出现。 一些地质特征，包括图案化的地面，构成了自然界中非生物自组织的一些最清晰、最容易理解的例子。 建议通过现场测量和计算机模拟受冻/融活动的土壤中离散粒子运动的协调程序来研究图案地面的自发出现和动力学。 这两种方法的紧密结合有望产生协同作用，模拟指导研究在现场提出新颖且更精确的问题，反之亦然。 通过整合以下具体目标，将获得一种新的、更基本的关于图案化地面作为自组织的主要例子的观点：（1）开发对反复冻融土壤中离散粒子运动的三维计算机模拟，并用它来研究冻土中图案的发展； (2) 测量石块和土壤的位移，记录模式的形成及其对扰动的反应，并使用自动仪器监测已建立的具有良好分类圆圈和条纹的研究地点的土壤温度、湿度和气候参数； (3)通过计算机模拟和实验室实验，构建图案化地面分选的微观力学模型； (4) 开发一个真实的传热传质模型，以研究形成排序圈的关键因素：活动层深度和传播冻结和融化锋面的三维几何形状。为冻土开发现实的近地表传热模型的一个重要的实际好处是，它有望有助于更准确地了解气候变化永久冻土地区的预期影响，以及永久冻土温度中包含的近期气候变化的记录。 拟议研究的目标是了解北极这些石头圈等图案从无序初始状态产生的过程：在本例中，是一个覆盖着 1-2 m 各种海滩沉积物的波浪切割平台。