Mesoscale Boundary Layer Structures Observed During the Lake-Induced Convection Experiment (Lake-ICE)

关于海-气相互作用的知识状况表明，目前的科学问题(如天气预报和全球变化)需要更多地了解复杂表面和天气条件下的海洋边界层。湖效应雪暴在秋季和冬季冷空气爆发期间在五大湖上空发展，对于研究复杂的边界层增长和中尺度环流模式是有用的“实验室”。最近的湖生对流实验(Lake-ICE)提供了一个独特的机会来深入了解对流边界层的发展，复杂条件下的中尺度环流，以及增长的边界层与周围天气条件之间的相互关系。主要研究人员过去的研究工作为研究强烈地表加热和强稳定上风条件下的湖泊效应边界滚流和中尺度雪带的发展提供了相当大的洞察力。然而，这些努力揭示了密歇根湖上风海岸附近大气和地表条件的重要性，那里没有观测数据。来自冰湖的数据可以直接检验这些假设，并扩大关于非经典的、复杂的地表和大气条件对边界层增长和中尺度环流模式的影响的知识。具体地说，主要研究人员建议(1)了解密歇根湖上滚动/蜂窝对流和边界层增长的演变，(2)确定天气条件、湖面温度变化和苏必利尔湖对大气质量的影响，对密歇根湖上的边界层增长和中尺度环流的影响，以及(3)确定控制大湖上不同尺度的湖泊效应涡旋演变的各自机制。对拟议的研究工作特别重要的是利用NCAR电子多普勒雷达(ELDORA)、WSR-88D和卫星观测来量化湖泊效应事件中的中尺度边界层环流模式的空间和时间变化。数值模拟工作将使用高级区域预测系统(ARPS)，以更好地了解导致复杂对流边界层中的中尺度环流模式变化和边界层增长的物理过程，并确定其特征在比仅靠观测所能获得的更大范围的大气条件下的敏感性。2.

The state of knowledge of air-sea interactions indicate that current scientific problems (such as weather forecasting and global change) require increased understanding of marine boundary layers in complex surface and synoptic conditions. Lake-effect snow storms, which develop over the Great Lakes during fall and winter cold air outbreaks, are useful "laboratories" for the study of complex boundary layer growth and mesoscale circulation patterns. Data collected during the recent Lake-Induced Convection Experiment (Lake-ICE) offer a unique opportunity to gain insight into the development of convective boundary layers, mesoscale circulations in complex conditions, and interrelationships between growing boundary layers and the ambient synoptic conditions.Past research efforts of the principal investigators have provided considerable insight into the development of lake-effect boundary roll convection and mesoscale snowbands in conditions of intense surface heating and strongly stable upwind conditions. However, these efforts revealed the importance of atmospheric and surface conditions close to the upwind shore of Lake Michigan, where no observational data were available. Data from Lake-ICE allow for direct testing of these hypotheses and an expansion of knowledge of the effects of non-classic, complex surface and atmospheric conditions on boundary layer growth and mesoscale circulation patterns. Specifically, the principal investigators propose to (1) understand the evolution of roll/cellular convection and boundary layer growth across Lake Michigan, (2) determine the influences of synoptic conditions, lake-surface temperature variations, and air-mass modification by Lake Superior, on boundary layer growth and mesoscale circulations over Lake Michigan, and (3) determine the respective mechanisms controlling the evolution of lake-effect vortices of different scales over the Great Lakes.The proposed research will utilize the unique dataset available from the 1997/1998 field operations of the Lake-ICE, supplemented with data taken during two past field experiments conducted over the Great Lakes. Of particular importance to the proposed research efforts will be the use of the NCAR Electra Doppler Radar (ELDORA), WSR-88D, and satellite observations to quantify spatial and temporal variations in mesoscale boundary layer circulation patterns in lake-effect events. Numerical modeling efforts will use the Advanced Regional Prediction System (ARPS) to develop a better understanding of the physical processes responsible for variations in mesoscale circulation patterns and boundary layer growth in complex convective boundary layers and to determine the sensitivity of their characteristics over a wider range of atmospheric conditions than can be obtained by observations alone. 2