Orographic Influences on Lake-Effect Storms

安大略冬季（OW）湖泊效应系统（LeS）实地活动将涉及多所大学和非营利组织团体，他们将在星期内更好地了解控制美国五大湖地区及其周围强降雪和相关云结构的时间和位置的机制。 OWLeS期间部署的观测资产包括怀俄明州空中国王大学、CSWR多普勒轮式移动的雷达、多个探测系统、米勒斯维尔大学剖面系统、UAH移动的综合剖面系统以及各种其他地面原位仪器。 这个特殊的研究小组的活动的重点是在LeS和更高的地形的影响，例如，由纽约州北部的拖船山高原地区代表的交叉点。 他们将利用气候分析、实地研究、真实数据数值模拟和理想化大涡模拟来解决与LeS相关的两个首要问题：1）环境条件、云过程、湖泊形状和大小以及地形尺度和几何形状之间的相互作用如何影响湖泊效应风暴期间的地形增雨？2）在什么条件下，地形改变了LeS的形态以及周围低地地区降水的产生、分布和强度？研究的主要区域将是大盐湖周围的地区和安大略湖下风处的塔格山高原。 该小组计划为OWLeS实地工作提供两个积雪观测站和一个可部署的无线电探空系统。 这项工作的智力价值集中在以下三个主要假设的评价：1）相对于下游障顶的覆盖逆温或稳定层的高度调节地形降水增强和低地与山地降水的比例; 2）冰粒的增长和湖效应系统的沉降以及边界层湍流是无阻塞湖泊地形降水的重要贡献者-影响事件;大的湖陆温差和陆风辐合导致湖控事件，而地形主导事件则发生在湖陆温差较弱的时段。 该项目的更广泛影响将包括本科生参与数据收集、教育和培训两名研究生（其中一名来自代表性不足的大气科学群体）以及各种外联活动。 这项研究有可能有助于改善对湖泊效应大雪风暴事件的预测，这反过来又会支持社会和经济效益。

The Ontario Winter (OW) Lake-effect Systems (LeS) field campaign will involve multiple university and non-profit organizational groups who week to better understand mechanisms controlling the timing and location of heavy snowfall and associated cloud structures over and around the U.S. Great Lakes region. Observational assets to be deployed during OWLeS include the University of Wyoming King Air, the CSWR Doppler on Wheels mobile radars, multiple sounding systems, the Millersville University Profiling System, the UAH Mobile Integrated Profiling System, and a variety of other surface in-situ instruments. The focus of this particular research team's activities is on the intersection of LeS and influences of higher terrain, e.g. as represented by the Tug Hill Plateau region of upstate New York. They will make use of climatological analysis, field research, real-data numerical modeling and idealized large-eddy simulations to address two overarching questions related to LeS: 1) How does the interplay between environmental conditions, cloud processes, lake shape and size, and terrain scale and geometry affect orographic precipitation enhancement during lake-effect storms?; and 2) Under what conditions does orography modify the morphology of LeS and the generation, distribution, and intensity of precipitation over surrounding lowland areas?The main regions of study will be areas around the Great Salt Lake and the Tug Hill Plateau downwind of Lake Ontario. This team plans to contribute two snow observation stations and a deployable rawinsounding system to OWLeS field effort. The intellectual merit of this effort is centered on evaluation of the following three main hypotheses: 1) The height of the capping inversion or stable layer relative to the downstream barrier crest regulates orographic precipitation enhancement and the lowland to mountain precipitation ratio; 2) Ice particle growth and fallout from the lake-effect system and boundary layer turbulence are important contributors to orographic precipitation in unblocked lake-effect events; and 3) Large lake-land temperature contrasts and associated land-breeze convergence yield lake-dominated events, whereas terrain-dominated events occur during periods with weaker lake-land temperature contrasts. Broader impacts of the project will include the participation of undergraduate students in data collection, education and training of two graduate students, one of which is drawn from an underrepresented group in atmospheric sciences, and various outreach activities. This research has the potential to contribute to improved prediction of lake-effect heavy snow storm events, which would in turn support both societal and economic benefits.