Storm Morphology and the Influence of Orography on Lake-Effect Precipitation

湖效应降水既是重大的天气灾害，也是美国五大湖等地区的经济驱动力。在过去的几十年里，湖效应降雪的预报已经有所改善，但是关于在湖效应事件中可能对降雪分布产生重大影响的具体过程，仍然存在一些悬而未决的问题。这项研究奖励将解决的一个因素是地形在决定湖泊效应降水影响方面的作用。关于地形如何影响湖效应降水的普遍理解是，附近丘陵或山脉提供的抬升导致对流的增强，从而导致降水。然而，最近的研究发现，情况并非总是如此，在某些地形区域，风暴深度和对流强度会减少。本项目将通过分析来自两个不同地区的观测数据来解决地形和湖效应降水问题：纽约安大略湖下游的拖船山高原，在2013-14年安大略省冬季湖效应系统（OWLeS）活动期间使用了大量仪器，以及日本的本州岛，由于日本海上空的长时间提取，那里收到了大量的湖效应降雪。将进行分析和建模工作，以利用地理、地形和湖效应风暴特征的鲜明对比，扩大对地形对湖效应降水影响的理解。该奖项的影响应该是改善湖泊影响地区的天气和气候预报，以及加强与从事类似问题的国际科学家的合作。该奖项的结果将通过多种方式传播，包括一个经常访问的博客网站和通过K-12外展。多名研究生将参与研究，确保培养下一代科学家。该奖项将通过对纽约拖轮山高原和日本本州岛湖效应风暴的观测分析和数值模拟，提高对地形如何影响湖效应降雪的理解。这两个地区有大量的湖泊或海洋效应降雪，但很少有关于产生降水增强的机制的比较。该项目的总体目标是提高对丘陵、山脉和高地地区对湖效应降水影响的认识和预测。将解决三个主要的科学问题：1)地形的存在如何影响湖效应降水的发生、分布和强度？2)湖效应风暴期间控制地形比例（低地与高地）的关键机制是什么？3)地形比如何随环境条件、云过程、湖泊形状和大小、地形尺度和几何形状而变化？

Lake-effect precipitation is both a significant weather hazard and an economic driver for locations like the US Great Lakes. Forecasts of lake-effect snow have improved over the past few decades, but there are still outstanding questions about specific processes that can have a major impact on the distribution of snowfall during a lake-effect event. One factor that will be addressed by this research award is the role of topography in determining the impact of lake-effect precipitation. The prevailing understanding of how topography affects lake-effect precipitation is that the lift provided by nearby hills or mountains results in an invigoration of the convection and therefore the precipitation. However, recent research has discovered that this is not always the case, and that there is a decrease in storm depth and convective vigor in certain topographic areas. This project will address the issue of topography and lake-effect precipitation through analysis of observations from two distinct areas: the Tug Hill plateau downstream of Lake Ontario in New York, which was heavily instrumented during the 2013-14 Ontario Winter Lake-effect Systems (OWLeS) campaign, and Honshu Island in Japan which receives copious amounts of lake-effect snow due to the long fetch over the Sea of Japan. Analysis and modeling efforts will be conducted to take advantage of the stark contrasts in geographic, topographic, and lake-effect storm characteristics to broaden the understanding of orographic influences on lake-effect precipitation. The impact of this award should be improved weather and climate forecasts in lake-effect regions as well as enhanced collaboration with international scientists working on similar issues. The results of the award would be disseminated through multiple means including a frequently visited blog site and through K-12 outreach. Multiple graduate students would be involved in the research, ensuring training of the next generation of scientists. This award will improve understanding of how orography affects lake-effect snowfall through observational analysis and numerical modeling of lake-effect storms on the Tug Hill Plateau of New York and Honshu Island in Japan. These two regions have prolific amounts of lake or ocean-effect snowfall, but there has been little comparison of the mechanisms that produce the precipitation enhancement. The overall goal of the project is to advance knowledge and prediction of the influence of hills, mountains, and upland regions on lake-effect precipitation. Three main scientific questions would be addressed: 1) How does the presence of topography affect the initiation, distribution, and intensity of lake-effect precipitation? 2) What are the key mechanisms controlling the orographic ratio (lowland vs upland) during lake-effect storms? 3) How does the orographic ratio vary with environmental conditions, cloud processes, lake shape and size, and terrain scale and geometry?