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

从无序到有序的出现在广泛的复杂动力系统中被观察到。 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我组织的一些最清晰和最容易获得的例子。 建议通过一个协调的程序，现场测量和计算机模拟的离散颗粒在土壤中的运动受到冻融活动的图案地面的自发出现和动力学进行调查。 这两种方法的紧密结合有望产生协同作用，模拟指导调查在该领域提出新颖和更精确的问题，反之亦然。 通过以下具体目标的整合，将获得一个新的和更基本的观点，即图案化地面作为自组织的一个主要例子：（1）开发一个三维计算机模拟的离散颗粒运动在土壤受到反复冻融，并使用它来研究图案的发展在冻土中;（2）测量石头和土壤的位移，记录模式的形成及其对干扰的反应，并在具有良好分类的圆圈和条纹的既定研究地点用自动化仪器监测土壤温度、湿度和气候参数;（3）通过计算机模拟和实验室实验，建立了图案化地面分选的微观力学模型;（4）建立了一个真实的热质传递模型，以研究形成分选圈的关键因素：活动层深度和三维几何形状的传播冻结和解冻前线。一个重要的实际好处是开发一个现实的近地表热传递模型的冻土是，它有望有助于更准确地了解气候变化的预期影响永久冻土区，和记录最近的气候变化，是在永久冻土温度。 拟议研究的目标是了解北极这些石头圈图案从无序初始状态产生的过程：在这种情况下，波浪切割平台覆盖着1-2米的各种海滩沉积物。

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.