Collaborative Research: Effects of Non-Uniform Surface Conditions on Lake-Effect Systems

观测和数值模拟研究极大地提高了对“经典”湖泊效应暴风雪的认识，并改进了对它们的预测。特别是对湖效应对流边界层生长和中尺度环流机制的研究，以及它们与海洋边界层的区别，有助于促进这些改进。此外，这些早期研究的结果和工具允许对与“非经典”湖效应风暴相关的复杂过程进行初步调查，其中湖效应系统受到天气或次天气现象的影响，或逆风气团受到邻近湖泊的影响。作为先前NSF支持研究的结果，首席研究员报告了几个非经典湖泊效应系统的调查，包括：(1)由较高云层播种湖效应云引起的降雪增强，(2)在湖泊上空形成的对流云带，并穿过中间的陆地延伸到第二个顺风湖泊，以及(3)与大型中纬度湖泊相互作用导致的天气锋改变。该研究项目旨在以过去的研究成果为基础，利用新的观测和数值模型来解决未解决的科学问题，以扩大对非经典湖泊效应系统和环境的理解。具体的研究目标是：(1)利用五大湖冰盖-大气通量（GLICAF）项目的独特观测资料，了解和量化地表通量与非均匀浮冰浓度的关系；(2)利用案例研究、气候和数值模式模拟，了解多湖带的结构以及环境参数对其发展和演变的影响；(3)量化天气锋与湖效应系统相互作用时环境条件对冷锋结构和演变的影响；(4)利用多普勒雷达测量，结合大气和环境数据集，确定中纬度小湖泊与湖效应系统相关的中尺度降雪事件的有利条件和组织；(5)研究云和冰的光谱特征以及辐射通量剖面。跨越一系列湖泊效应系统。这项研究的结果将对复杂的过程提供有价值的见解，这些过程往往使五大湖地区常见的中尺度现象的冬季预报复杂化。这些结果将通过期刊和会议文章传达给气象界，并通过国家气象局办公室的区域研讨会和报告传达给业务界。

Observational and numerical modeling studies have greatly improved the understanding of "classic" lake-effect snowstorms and led to improvements in forecasting them. In particular, research focused on the mechanisms leading to lake-effect convective boundary layer growth and mesoscale circulations, and how they differ from oceanic marine boundary layers, has helped stimulate these improvements. In addition, results and tools from these earlier research studies have allowed for initial investigations of complex processes associated with "non-classic" lake-effect storms, where lake effect systems are modified by synoptic or sub-synoptic phenomena or upwind air masses are modified by neighboring lakes. As a result of prior NSF supported research, the Principal Investigators reported on investigations of several non-classic lake-effect systems including (1) enhanced snowfall caused by seeding of lake-effect clouds by higher level cloud layers, (2) convective cloud bands that develop over a lake and extend across an intervening land mass to a second downwind lake, and (3) synoptic frontal modifications resulting from the interaction with a large mid-latitude lake. This research project seeks to build on past research results and address unanswered scientific questions using new observations and numerical models to broaden understanding of non-classic lake-effect systems and environments. Specific research objectives are to: (1) use unique observations from the Great Lakes Ice Cover-Atmospheric Flux (GLICAF) project to understand and quantify the relationship of surface fluxes to heterogeneous pack ice concentrations, (2) use case-study, climatic, and numerical model simulations to understand the structure of multiple-lake bands and the influence of environmental parameters on their development and evolution, (3) quantify the influence of environmental conditions on cold frontal structure and evolution as synoptic fronts interact with lake-effect systems, (4) use Doppler radar measurements, accompanied by atmospheric and environmental datasets to determine the favorable conditions and the organization of mesoscale snow events associated with lake-effect systems over small mid-latitude lakes, and (5) examine cloud and ice spectrum characteristics, as well as radiative flux profiles, across a range of lake-effect systems. Results of this research will give valuable insight into complex processes that often complicate winter forecasting of mesoscale phenomena common to the Great Lakes region. These results will be communicated to the meteorological community through journal and conference articles and to the operational community through regional workshops and presentations at National Weather Service offices.