EAPSI: Lake-Effect Precipitation Processes Over Hokkaido Island, Japan

湖、海、洋效应（以下简称湖效应）暴风雪发生在大片水域的下游，如北美五大湖和日本海。这些高度局部化的风暴会给城市和农村地区带来大雪，影响当地的交通、公用事业、教育和商业。天气预报员和天气预报模型目前正在努力准确预测这场大雪的大小、时间和空间分布。提高对湖效应风暴降水过程的认识，对于提高湖效应风暴的预报能力是必不可少的。这项研究将与北海道大学低温科学研究所的著名湖泊效应降雪专家Yasushi Fujiyoshi博士合作进行。北海道岛每年的降雪大部分来自湖泊效应事件，本研究将使用观测数据和风暴模拟来分析2013-2014年冬季影响北海道岛的湖泊效应事件。湖效应降雪的大小、时间和空间分布受观测到的水成物类型的时空格局和风暴内部的边缘程度的强烈影响。本研究将利用大气探测、地表雪晶观测、双极化雷达、卫星影像等观测资料，以及数值模式模拟，研究影响北海道湖效应风暴的降水结构和水文气象类型分布，并探讨这些因素如何影响日本海湖效应降水的强度、时间和分布。对来自纽约安大略湖和犹他州大盐湖的湖效应事件的分析，这些都是较小的水体，也将被纳入相关微物理过程的比较中，以促进我们对这种现象在许多尺度和地理位置上的理解。NSF EAPSI奖是与日本科学促进会合作资助的。

Lake-, sea-, and ocean-effect (hereafter referred to as lake-effect) snowstorms occur downstream of large bodies of water, such as the Great Lakes of North America and the Sea of Japan. These highly localized storms can bring heavy snowfall to urban and rural areas, impacting local transportation, utilities, education, and commerce. Weather forecasters and weather prediction models currently struggle with accurately predicting the magnitude, timing, and spatial distribution of this heavy snowfall. An improved understanding of precipitation processes in lake-effect storms is imperative to improving forecast skill during these events. This study will be conducted in collaboration with Dr. Yasushi Fujiyoshi, a noted expert on lake-effect snowfall, at the Institute for Low Temperature Science at Hokkaido University. The island of Hokkaido receives much of its annual snowfall from lake-effect events, and this study will involve the analysis of a lake-effect event that impacted Hokkaido Island during winter 2013-2014 using both observational data and simulations of the storm.The magnitude, timing, and spatial distribution of lake-effect snowfall is strongly influenced& by the spatial and temporal patterns of observed hydrometeor types and the degree of riming within the storm. Using observational data such as atmospheric soundings, surface snow crystal observations, dual-polarization radar, and satellite imagery, as well as numerical model simulations, this research will examine the precipitation structures and hydrometeor-type distributions within a lake-effect storm affecting Hokkaido Island and will explore how these factors affect the intensity, timing, and distribution of lake-effect precipitation over the Sea of Japan. Analysis of lake-effect events from Lake Ontario, New York, and the Great Salt Lake, Utah, which are smaller bodies of water, will also be incorporated into a comparison of the relevant microphysical processes in order to advance our understanding of this phenomenon across many scales and geographical locations. This NSF EAPSI award is funded in collaboration with the Japan Society for the Promotion of Science.