Orographic Influences on Lake-Effect Precipitation

地形对湖效应暴风雪有着巨大的影响，不仅在像犹他州北部的大盐湖盆地这样有主要山脉屏障的地区，而且在美国东部和加拿大，在五大湖周围也有较小的起伏。例如，在位于安大略湖下游的纽约北部拖船山高原上，海拔每上升100米，年降雪量就会增加25-50毫米，在极端的湖泊效应事件中，风暴总累积量达到360厘米。地形也通过改变大尺度流与大面积降水屏障和岸线带等降水结构发展之间的关系来改变湖效暴风雪的形态。了解湖泊地形降水过程不仅对天气预报很重要，而且在水文学、生态学和地貌学方面也有重要的应用。该项目的主要目标是提高对湖泊地形降水过程及其对湖效应区天气和气候影响的认识。需要研究的关键问题包括：(1)地形在多大程度上改变了湖效暴雪的形态；(2)哪些地形过程和现象导致了这些改变；(3)湖泊地形降水过程在多大程度上影响了湖效区的水文气候。这些问题将在一项为期三年的研究计划中得到解决，该计划将考察两个地区，这些地区的地形对湖效应降水有很强的影响。第一个是犹他州北部的大盐湖盆地，那里的瓦萨奇山脉和其他山脉高出湖面2000米。第二个是纽约北部的托格山高原，它提供了安大略湖上方400-500米的广阔高地。这项研究将产生基于雷达的气候学、实地活动和数值模拟的综合结果。智力价值：这项研究将促进对控制湖效应和地形降水的物理过程的认识和理解，反过来，这些过程对湖效应地区的水文气象学的影响。建立大规模水流和湖效应形态之间关系的努力已被证明具有挑战性，之前的工作人员特别确定需要更好地理解地形在改变结构过渡带中的作用。项目结果将满足这一需求。更广泛的影响：该项目解决了改善湖泊影响地区天气和气候预测的社会需求。其他更广泛的影响包括：(1)将研究成果注入到本科和研究生课程、培训课程和基于网络的教育模块中；(2)对两名研究生的指导和扩大女性参与国家科学基金会资助的项目；(3)通过与美国国家科学基金会K-12研究生奖学金项目的合作，提高公众对科学的理解，该项目让研究生研究人员在盐湖城学区的K-12课堂上教授基于发现的环境科学。此外，这项研究计划可能会在其他相关研究领域引起广泛的科学兴趣，如水文学、生态学和地貌学。

Orography has a dramatic influence on lake-effect snowstorms, not only in regions with major mountain barriers such as the Great Salt Lake Basin of northern Utah, but also in the eastern United States and Canada where more modest relief is found around the Great Lakes. For example, over the Tug Hill Plateau of northern New York, which lies downstream of Lake Ontario, annual snowfall increases 25-50 mm for every 100 m rise in elevation and storm-total accumulations have reached 360 cm in extreme lake-effect events. Orography also modifies the morphology of lake-effect snowstorms by altering the relationship between the large-scale flow and the development of precipitation structures such as broad-area precipitation shields and shoreline bands. Knowledge of lake-orographic precipitation processes is important not only for weather prediction, but also applications in hydrology, ecology, and geomorphology.The primary goal of the project is to improve understanding of lake-orographic precipitation processes and their influence on the weather and climate of lake-effect regions. Key questions to be investigated include: (1) to what extent does orography modify the morphology of lake-effect snowstorms, (2) which orographic processes and phenomena are responsible for these modifications, and (3) to what degree do lake-orographic precipitation processes contribute to the hydroclimate of lake effect regions? These questions will be addressed in a three year research program that examines two regions where there are strong orographic influences on lake-effect precipitation. The first is the Great Salt Lake basin of northern Utah where the Wasatch Mountains and other ranges rise up to 2000 m above lake level. The second is the Tug Hill Plateau of northern New York, which provides a broad upland region 400-500 m above Lake Ontario. The research will produce a synthesis of results from a radar-based climatology, a field campaign, and numerical modeling.Intellectual merit: The research will advance knowledge and understanding of the physical processes that control lake-effect and orographic precipitation and, in turn, the influence of these processes on the hydrometeorology of lake-effect regions. Efforts to establish a relationship between the large-scale flow and lake-effect morphology have proven challenging, with previous workers specifically identifying the need to better understand the role of orography in altering structural transition zones. Project results will address this need.Broader impacts: The project addresses the societal need to improve weather and climate prediction in lake-effect regions. Other broader impacts include:(1) the infusion of research findings into undergraduate and graduate courses, training courses, and web-based educational modules, (2) the mentoring of two graduate students and the broadening of the participation of women in NSF-sponsored programs, and (3) the enhancement of public scientific understanding through collaborations with an NSF GK-12 graduate fellowship program that involve graduate student researchers in K-12 classrooms to teach discovery based environmental science in Salt Lake City school districts.Further, this research program will likely engender broad scientific interest in other allied research communities such as hydrology, ecology, and geomorphology.