Continued Lidar and Numerical Investigation of the Internal Boundary Layer Observed During Lake-Ice

推动大气循环的大部分能量是通过与地表的热量、水分和动量交换而获得的。为了研究五大湖上空的这些过程，1997/98年冬季在密歇根湖上空举行了一个名为湖泊诱导对流实验(Lake-ICE)的项目。威斯康星大学体积成像激光雷达在Lake-ICE野外项目中获得了一个独特的数据集。这些数据将用于验证微尺度大气边界层模型的性能，这是在冰湖事件期间开始的研究的继续。模型模拟将使用威斯康星大学的非静力建模系统。模式结果将直接与VIL观测到的边界层结构特征进行比较，这项工作是为了模拟受当地地形和土地利用特征强迫的大尺度流动和微尺度流动结构的演变。公共部门、私营部门和军事部门对此类预测产品非常感兴趣。目前，对特定微尺度结构的模型模拟的有效性知之甚少。此外，对这种尺度上的流动动力学的了解主要局限于专注于恒定流动的统计特性的研究，而不是对特定的演变结构的直接模拟，这些结构可能与特定的地形特征有关，如丘陵、建筑物和湖岸几何形状。这是根据非常高分辨率的观测来验证微尺度特征的模型模拟的独特努力。项目目标是(1)评估微尺度模式对预测的大尺度流动演变的局部响应的能力，以及(2)增加对导致观测到的相干结构的作用力和动力学的理解。首席调查员将集中研究观察到的两种现象：(A)冰卷湖的成因和(B)12月21日观测到的沿海锋面。如果研究成功，这项研究将增进对大气边界层系统的了解，并发展对研究这类系统有用的分析方法。这可能有助于更好地理解和预测污染物在复杂地形中的传输和扩散等现象。

Much of the energy that drives atmospheric circulations is obtained through exchanges of heat, moisture, and momentum with the surface. To study these processes over the Great Lakes, a project known as the Lake-Induced Convection Experiment (Lake-ICE) was held over Lake Michigan in the winter of 1997/98. The University of Wisconsin Volume Imaging Lidar acquired a unique data set during the Lake-ICE field project. These data will be used to validate the performance of a microscale model of the atmospheric boundary layer in a continuation of the research begun during Lake-ICE. The University of Wisconsin Nonhydrostatic Modeling System will be used for the model simulations. Model results will be compared directly to the structural features of the boundary layer observed by the VIL using verification techniques developed under prior NSF support.This work is an effort to simulate both the evolution of the large-scale flow and the microscale flow structures, forced by local topographical and land use features. There is a great deal of interest by the public, private and military sectors in such forecast products. Currently little is known about the validity of model simulations of specific microscale structures. Moreover, understanding of the flow dynamics on this scale has been limited to mostly studies that focus on statistical properties of steady flow, rather than the direct simulation of specific evolving structures, which may be tied to specific topographic features such as hills, buildings, and lakeshore geometry. This is a unique effort to validate model simulations of microscale features against very high-resolution observations.Project goals are to (1) assess the ability of a microscale model to simulate the local response to predicted large scale flow evolution and (2) increase understanding of the forcings and dynamics leading to the observed coherent structures. The Principal Investigator will concentrate on two observed phenomena: (a) the genesis of Lake-ICE rolls and (b) the coastal front observed on 21 December.If successful, this research will advance knowledge of atmospheric boundary layer systems and develop analysis methodologies useful in studying such systems. This potentially could lead to better understanding and forecasting of such phenomena as the transport and diffusion of pollutants through complex terrain.