Gravity Waves, Lee Cyclones and Precipitation Bands

9708170月，拟议的研究涉及与中纬度气旋有关的现象的组织和演变及其对云、降水和其他气象要素的影响。具体地说，研究将集中在三个现象：中尺度重力波、背风气旋和中尺度降水带。在风暴尺度业务和研究气象锋面试验系统测试(STORM-FEST)期间获得的高空间和时间分辨率数据集为首席调查人员提供了进一步了解中尺度重力波的独特机会。人们怀疑这些重力波有时与当地的大雪有关。对观测的分析和正在进行的数值模拟研究将使人们能够调查产生和维持1992年2月14日至15日发生的明确的中尺度重力波的机制，以及该波与对流之间的相互作用。首席调查员对四个风暴气旋案例的观测分析提出了一些重要问题，涉及风暴前低层环境的可变性及其对风暴气旋内部锋面、嵌入降水和相关中尺度现象的结构和演变的影响。了解风暴前环境条件对背风气旋的形成、后续结构和演变的影响，对于发展一个全面的中纬度气旋模式至关重要。拟议研究的重点是研究高层前兆扰动、地面和高空锋面、背风气旋和中尺度降水带结构和演变变化背后的机制。对大雪带的研究将结合定于1997-98年冬季在大湖区进行的湖泊诱导对流实验(Lake-ICE)进行。冰湖是一个大型的、多个调查员参与的项目，旨在进一步了解五大湖对不同天气现象的影响。冰湖中心首席调查员的研究活动将包括对冬季气旋的演变以及气旋与湖泊相互作用时嵌入的中尺度过程进行详细的观测和模拟研究。这项研究的成功完成将带来更好的冬季天气概念模型，并最终可能带来更好的预报。***

9708170 Rauber The proposed research relates to the organization and evolution of phenomena associated with mid-latitude cyclones and their influence on clouds, precipitation and other meteorological elements. Specifically, research will focus on three phenomena: mesoscale gravity waves, lee cyclones, and mesoscale precipitation bands. The high spatial and temporal resolution data sets obtained during the Stormscale Operations and Research Meteorology-Fronts Experiment, Systems Test (STORM-FEST) provides the Principal Investigators with a unique opportunity to further understanding of mesoscale gravity waves. It is suspected that these gravity waves are sometime associated with locally heavy snowfalls. Analyses of observations and ongoing numerical modeling studies will enable the investigation of the mechanisms that generated and maintained a well-defined mesoscale gravity wave that occurred on 14-15 February 1992, as well as the interaction between the wave and the convection. Analyses by the Principal Investigators of observations for four STORM-FEST cyclone cases have raised important questions concerning the variability in the pre-storm low level environment and its influence on the structure and evolution of fronts, embedded precipitation and associated mesoscale phenomena within lee cyclones. Understanding the influence of pre-storm environmental conditions on the formation and subsequent structure and evolution of lee cyclones is critical toward developing a comprehensive model of mid-latitude cyclones. The focus of the proposed research is to investigate the mechanisms behind the variability of the structure and evolution of upper-level precursor disturbances, surface and upper level fronts, lee cyclones, and mesoscale precipitation bands. Research on heavy snowbands will be conducted in association with the Lake-Induced Convection Experiment (Lake-ICE) scheduled in the Great Lakes region in the winter of 1997-98. The Lake-ICE is a large, multi-investigator project that is designed to further understanding of the impact of the Great Lakes on different weather phenomenon. The research activities of the Principal Investigators within Lake-ICE will consist of detailed observational and modeling studies of the evolution of winter cyclones and embedded mesoscale processes as the cyclones interact with the Lakes. Successful completion of this research will lead to better conceptual models of wintertime weather and could eventually lead to better forecasts. ***