Convective Rolls and Cells in Lake-effect Snowstorms: Structures, Mechanisms and Effects

小行星9510098 为了充分确定天气尺度环流和地面特征之间的联系，必须了解对流边界层内的中尺度流动。观测证据表明，理论标准往往是不成功的预测中尺度对流组织的边界层。 特别是，边界层流动结构称为卷经常观察时，预测细胞对流。 拟议的研究旨在采用数值和观测技术：（1）确定控制湖泊效应暴风雪中边界层卷发展的因素;（2）确定对流的中尺度组织如何影响质量翻转率，降水率和边界层深度。 第一个目标将通过仔细记录密歇根湖东海岸附近中尺度对流的三维结构以及它如何随逆风大气条件和边界层风、温度和湿度（冰、液体和蒸汽）在整个湖上的分布演变而变化来实现。 将在观测条件范围内进行数值模拟，以提供更完整的数据集，用于确定风切变、潜热释放和其他因素对边界层对流组织的影响。 中尺度对流组织对质量翻转率、降水率和边界层深度的影响将通过仔细记录这些特征在快速变化的中尺度对流结构的观测和模拟中如何在下风海岸附近变化来完成。 这项工作是基于观测期间采取的芝加哥湖雪项目大学。 这项工作的数值方面将利用俄克拉荷马州大学风暴分析和预报中心开发的高级区域预报系统模型进行。 这项研究将是伊利诺斯州水资源调查局和南达科他州矿业和技术学院之间的合作努力。 ***

9510098 Kristovich Mesoscale flows within convective boundary layers must be understood in order to fully determine the link between synoptic-scale circulations and surface characteristics. Observational evidence suggests that theoretical criteria are often unsuccessful in predicting the predominant mesoscale convective organization in the boundary layer. In particular, boundary layer flow structure knows as rolls are often observed when cellular convection is predicted. The proposed study seeks to employ both numerical and observational techniques to: (1) determine factors which control the development of boundary layer rolls in lake-effect snowstorms; and (2) determine how the mesoscale organization of convection influences mass overturning rates, precipitation rates, and boundary layer depth. The first goal will be accomplished by careful documentation of the three-dimensional structure of mesoscale convection near the eastern shore of Lake Michigan and how it varies with upwind atmospheric conditions and evolution of boundary layer winds, temperature, and moisture (ice, liquid, and vapor) profiles across the lake. Numerical simulations will be carried out over the range of observed conditions to give a more complete data set for determining the influence of wind shear, latent heat release, and other factors, on the organization of boundary layer convection. The influence of mesoscale convective organizations on mass overturning rates, precipitation rates, and boundary layer depth will be accomplished by carefully documenting how these features change near the downwind shore in both observations and simulations of rapidly changing mesoscale convective structure. This work is based on observations taken during the University of Chicago Lake Snow Project. Numerical aspects of this work will be carried out with the Advanced Regional Prediction System model developed at the Center for Analysis and Prediction of Storms at the University of Oklahoma . This research will be a collaborative effort between the Illinois State Water Survey and the South Dakota School of Mines and Technology. ***