Collaborative Research: Multi-Scale Study of Lake Breezes and the Impact of Marine Boundary Layers on Convection in the Great Lakes Region

美国的海岸带对社会的许多方面都至关重要。一半以上的美国人口居住在海岸线80公里以内，4000多万人居住在大湖区。最常发生在春季和夏季的五大湖湖风可能会对沿海地区产生重大的经济、社会和气候影响。湖风环流可以通过提供较凉爽的温度，影响强雷暴的发展，影响降水量和地点，以及改变空气污染浓度和输送，从而显著改变近海环境。尽管对湖风进行了大量研究，对湖泊冷却、稳定的海洋边界层的研究较少，但对几个重要领域的基本科学认识仍然有限。许多数值模拟和实验室研究表明，城市地区对湖风(或类似的海风)环流有很大影响，通常导致湖风锋到达城市中心后内陆运动减少。目前，与非城市地区相比，关于海风和湖风通常如何在城市近岸地区附近移动的观测信息非常有限。对通过五大湖两个城市地区的湖风锋面运动的初步调查表明，预期的内陆运动减少的情况很少发生。这项研究试图确定这些地区湖风运动的变异性，并检查导致时空变化的环境条件。气象界最近有兴趣研究和了解中尺度系统与气候变异性之间的联系。五大湖的湖风为研究这一问题提供了一个难得的机会。过去对湖风发生的调查在不同的时间尺度上考察了大湖区有限的几个地点。这些研究提供了有关湖风时空变异性的重要但不完整的信息。这项研究试图量化五大湖湖风发生的年际、季节内和空间变化，并确定它们对近岸气候条件的影响。很少有研究探讨暖季海洋边界层对大湖区对流系统和降水分布的影响。事实上，预测界继续断言，大湖区夏季预报面临的最大挑战之一是，如果有的话，海洋层在穿越湖泊时将对现有对流系统产生影响。这项研究试图通过了解对流系统的演变与海层稳定性和环境条件之间的关系来解决这一问题上的知识差距。智力上的价值：这些研究的结果将为以下几个科学认识有限且往往相互冲突的领域提供新的见解：(A)城市地区对湖风锋面的影响以及环境条件对湖风对城市地区的影响；(B)湖风的年际、季节和空间变异性及其对沿海气候条件的影响；以及(C)对流系统与湖泊冷却的海洋边界层的相互作用。这些研究将涉及湖风的几个基本方面，并大大有助于了解五大湖对沿海城市地区、恶劣天气和降水系统以及区域气候条件的影响。更广泛的影响：研究结果将加深对沿海气象的了解，沿海气象影响到与商业、工业、交通、健康、安全、娱乐和国防有关的一系列活动。正如最近向更大的大气科学界建议的那样，这项研究将通过使用观测数据来研究大气-陆地相互作用、陆地-海风的影响以及中尺度系统的气候学，从而改进对区域气候模拟的评估。此外，这项研究将显著有助于造福下一代科学家。本科生将通过参加霍巴特和威廉·史密斯学院既定的暑期研究项目来参与其中。研究生将受益于积极参与伊利诺伊大学和伊利诺伊州水调查的一个成功的研究项目。结果将通过期刊文章和会议介绍向科学界广泛传播，并通过区域讲习班和专题介绍向业务预报和空气质量界广泛传播。

Coastal zones of the United States are crucially important to many aspects of society. More than half of the United States population lives within 80 km of a coastline and greater than 40 million people reside in the Great Lakes region. Great Lakes lake breezes, which occur most often during the spring and summer months, can have large economic, societal, and climatic impacts on coastal regions. Lake-breeze circulations can significantly modify the near coastal environments by providing cooler temperatures, affecting the development of severe thunderstorms, influencing precipitation amounts and locations, and altering air pollution concentrations and transport. Despite considerable research on lake breezes, and to a lesser amount on lake-cooled, stable marine boundary layers, limited fundamental scientific understanding of several important areas remain. A number of numerical modeling and laboratory studies suggest that urban areas have large impacts on lake-breeze (or similar sea-breeze) circulations, generally resulting in a decrease in inland movement after the lake-breeze front has reached the urban center. At present, there exists very limited observational information on how sea- and lake-breezes typically move in the vicinity of near-shore urban areas as compared to non-urban areas. A preliminary investigation of lake-breeze frontal movement through two urban areas in the Great Lakes suggests that the expected decrease in inland movement occurs infrequently. This research seeks to determine the variability of lake-breeze movement in these areas and examine the environmental conditions that contribute to the spatial and temporal variations. There has been recent interest within the meteorological community in examining and understanding the connections between mesoscale systems and climate variability. Great Lakes lake breezes provide an exceptional opportunity to examine this issue. Past investigations of lake-breeze occurrence have examined a limited number of locations in the Great Lakes region over varying timescales. These studies have provided important, but incomplete, information about the spatial and temporal variability of lake breezes. This research seeks to quantify the inter-annual, intra-seasonal, and spatial variations in Great Lakes lake-breeze occurrence and determine their impact on near-shore climate conditions. Few studies have examined the influence of the warm-season marine boundary layers on convective systems and the precipitation distribution in the Great Lakes region. In fact, the forecasting community continues to assert that one of the most significant summer forecast challenges in the Great Lakes region is the impact, if any, that the marine layer will have on an existing convective system as it crosses a lake. This research seeks to address the gap of knowledge on this issue by understanding the relationship between the evolution of convective systems and marine layer stability and environmental conditions.Intellectual Merit: Results of the studies will provide new insight into several areas of limited and often conflicting scientific understanding: (a) the influence of urban areas on lake-breeze fronts and the impact of environmental conditions on the lake breeze response to urban areas, (b) the inter-annual, intra-seasonal, and spatial variability of lake breezes and their influence on coastal climate conditions, and (c) the interaction of convective systems with lake-cooled marine boundary layers. These studies will address several fundamental aspects of lake breezes and significantly contribute to the understanding of the impact the Great Lakes have on coastal urban areas, severe weather and precipitation systems, and regional climate conditions. Broader Impacts: Results of the studies will provide an enhanced understanding of coastal meteorology which affects a host of activities related to commerce, industry, transportation, health, safety, recreation, and national defense. As recently recommended to the larger atmospheric science community, the research will examine air-land interactions, the effects of land-sea breezes, and the climatology of mesoscale systems through the use of observational data subsequently allowing for improved evaluation of regional climate simulations. In addition, the research will notably contribute to benefiting the next generation of scientists. Undergraduate students will be involved through participation in the established summer research program at Hobart and William Smith Colleges. Graduate students will benefit by active participation in a successful research program at the University of Illinois and Illinois State Water Survey. Results will be widely communicated to the scientific community through journal articles and conference presentations and to the operational forecast and air quality communities through regional workshops and presentations.