Collaborative Research: Investigations of Non-Classic Lake-Effect Boundary Layer Processes

研究和业务天气观测系统和数值模拟技术的进步使人们对湖泊效应雪暴的发展和演变所涉及的物理过程的了解逐步提高。特别是，最近在湖泊诱导对流实验期间进行的观测和中尺度数值模式被用来更好地理解孤立的“经典”湖泊效应系统，这些系统主要是从秋季和冬季湖面的热量和水汽通量发展而来的。对经典湖效系统中微尺度和中尺度过程之间相互作用的科学理解的加强，现在可以应用于更复杂，也许更常见和更强烈的非经典湖效风暴。这项合作研究项目将建立在过去研究成果的基础上，并使用新的观测和数值模式来发展对天气系统和中尺度湖效系统的复杂相互作用以及控制中尺度湖效对流带的相干性和结构的因素的物理一致性的理解。特别是，首席调查员将分析从雷达、飞机、卫星和地面仪器获得的数据，并进行详细的中尺度模式模拟，以研究非典型湖泊效应情况下的悬而未决的问题。四个具体的研究目标是：1)确定在有和没有大尺度降水的情况下发生在高空的湖泊效应边界层的云微物理结构和热力学的差异；2)确定暖湖对移动的中尺度降水系统(如与天气锋面有关的)中尺度动力学和结构的影响；3)确定来自上风向湖泊的对流边界层和中尺度环流影响顺风向湖泊上方湖泊效应发展的过程；4)确定导致沿着湖效雪带发展的中尺度结构的动力学机制以及垂直风切变对波段结构一致性的影响。这项研究的成功完成可能有助于提高对强烈湖泊效应暴风雪的预测。

Advances in research and operational weather observation systems and numerical modeling techniques have led to progressive improvements in understanding of physical processes involved in the development and evolution of lake-effect snow storms. In particular recent observations taken during the Lake-Induced Convection Experiment (Lake-ICE) and mesoscale numerical models have been utilized to better understand isolated "classic" lake-effect systems that develop primarily from lake surface heat and moisture fluxes in fall and winter months. The enhanced scientific understanding of interactions between microscale and mesoscale processes in classic lake-effect systems can now be applied to more complex, and perhaps more common and intense, non-classic lake-effect storms.This collaborative research project will build on past research results and use new observations and numerical models to develop a physically-consistent understanding of complex interactions of synoptic systems and mesoscale lake-effect systems and factors controlling the coherence of, and structure along, mesoscale lake-effect convective bands. In particular the Principal Investigators will analyze data obtained from radars, aircraft, satellites and surface instrumentation and perform detailed mesoscale model simulations to study unresolved issues for non-classic lake-effect situations. Four specific research objectives are to: 1) Determine differences in the cloud microphysical structure and thermodynamics of lake-effect boundary layers that occur with and without large-scale precipitation aloft; 2) Determine the effects of a warm lake on the mesoscale dynamics and structure of moving mesoscale precipitation systems (such as associated with synoptic fronts); 3) Determine the processes by which the convective boundary layer and mesoscale circulations from an upwind lake influence lake-effect development over a downwind lake; 4) Determine the dynamic mechanisms leading to the development of mesoscale structures along lake-effect snow bands and the influence of vertical wind shear on band structural coherence. Successful completion of this research could help improve the forecast of intense lake-effect snowstorms.