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

9707165埃洛兰塔 驱动大气环流的大部分能量是通过与地表交换热量、水分和动量获得的。 湖泊效应天气事件，即冷空气团在五大湖上空迅速改变，是研究这些交换的极好的自然实验室。湖诱导对流实验（湖-ICE）是一个多个主要研究者项目，旨在利用这个自然实验室来确定边界层生长过程是如何被中尺度边界层对流结构控制的，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，首席研究员将研究密歇根湖逆风海岸附近边界层演变的四维特征。为了实现这一目标，首席研究员将在Lake-ICE项目期间在密歇根湖西海岸部署和操作体积成像激光雷达（VIL）。 当冷空气经过温暖的水面时，激光雷达将观测到湖面上不断增长的对流边界层。 这些观测将补充计划用于中湖区和东海岸的机载和地基雷达测量，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将重复扫描延伸到顺风21公里的三维体积。 这些气溶胶后向散射的图像将记录下空气顺风移动时对流的增长。 具体而言，将对激光雷达数据进行分析，以提供：1）作为顺风距离的函数的边界层的深度，2）作为顺风距离和高度的函数的风速和风向，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）第一次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，主要研究人员将评估大涡模拟的能力，以获得对流场的明确描述。 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具有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. ***