The Use of 4-Dimensional Lidar Data to Evaluate Large Eddy Simulations: A Lake ICE Project

9707165埃罗兰塔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。湖泊效应天气事件是研究这些交换的极好的自然实验室，在五大湖上空冷气团被迅速修改。湖泊诱导对流实验(Lake-ICE)是一个多主体研究项目，旨在利用这个自然实验室来确定边界层增长过程如何受到中尺度边界层对流结构的控制，以及修改后的边界层如何影响降水的产生和更大尺度的气象条件。在这项研究工作中，首席调查员将研究密歇根湖上风海岸附近边界层演变的四个维度特征。为了实现这一目标，首席调查员将在Lake-ICE项目期间在密歇根湖西岸部署和操作一台体积成像激光雷达(VIL)。激光雷达将观察到当冷空气经过温暖的水域时，湖面上不断增长的对流边界层。这些观测将补充计划在湖心区和东岸进行的机载和地面雷达测量，并将与其他研究气象测量相协调。在典型的数据会话期间，VIL将重复扫描顺风向延伸21公里的三维体积。这些气溶胶后向散射图像将记录空气顺风移动时对流的增长。具体地说，激光雷达资料将被分析以提供：1)边界层深度作为下风距离的函数，2)风速和风向作为下风距离和高度的函数，3)对流羽流的尺寸和纵横比，4)对流场中对流单体的空间组织，5)对流结构的去相关时间，6)第一云形成的顺风距离和高度。激光雷达数据的主要应用将是评估湖上边界层的数值模型。此外，首席调查人员将评估大涡模拟得出对流场的显式描述的能力。这项研究的成功完成将增加对湖泊边界层演变的基本了解，这对于理解和预测非常破坏性的湖泊效应雪事件至关重要。***

9707165 Eloranta Much of the energy that drives atmospheric circulations is obtained through exchanges of heat, moisture, and momentum with the surface. Lake-effect weather events, where cold air masses are rapidly modified over the Great Lakes, are excellent natural laboratories for studying these exchanges. The Lake-Induced Convection Experiment (Lake-ICE) is a multiple-Principal Investigator project which seeks to use this natural laboratory to determine how boundary layer growth processes are controlled by mesoscale boundary layer convective structures and how the modified boundary layer effects the production of precipitation and the larger scale meteorological conditions. In this research effort, the Principal Investigator will study the four dimensional characteristics of the evolution of the boundary layer near the upwind shore of Lake Michigan. To accomplish this, the Principal Investigator will deploy and operate a Volume Imaging Lidar (VIL) on the west shore of Lake Michigan during the Lake-ICE project. The lidar will observe the growing convective boundary layer over the lake as cold air passes over the warm water. These observations will complement airborne and ground-based radar measurements planned for mid-Lake area and the eastern shore and will be coordinated with other research meteorological measurements. During a typical data session, the VIL will repetitively scan a three-dimensional volume extending to 21 km downwind. These images of aerosol backscatter will record the growth of convection as the air moves downwind. Specifically, the lidar data will be analyzed to provide: 1) the depth of the boundary layer as a function of distance downwind, 2) the wind speed and direction as a function of downwind distance and altitude, 3) the dimensions and aspect rations of the convective plumes, 4) the spatial organization of the convective cells in the convective field, 5) the decorrelation time for convective structures, 6) the d ownwind distance and altitude of first cloud formation. The primary application of the lidar data will be to evaluate numerical models of the boundary layer over the lake. In addition, the Principal Investigators will evaluate the ability of a large eddy simulation to derive an explicit description of the convective field. Successful completion of this research will increase fundamental understanding of the evolution of the lake boundary layer which is crucial to understanding and forecasting the very disruptive lake-effect snow events. ***