Collaborative Research: Toward an Improved Understanding of the Characteristics, Processes, and Impacts of Northerly and Southerly Low-Level Jets in the Central United States

合作研究：更好地了解美国中部偏北和偏南低空急流的特征、过程和影响

• 批准号: 0924816
• 负责人: Julie Winkler
• 金额: $ 42.16万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0924816&HistoricalAwards=false
• 关键词: Collaborative; Research; Toward; Improved; Understanding

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Low-level jets are streams of fast-moving air in the lower troposphere. Both northerly (N-LLJs) and southerly (S-LLJs) low-level jets occur frequently in the central United States and have a significant impact on regional weather and climate, precipitation and water resources, and wind energy. The causes of low-level jets are complex, with both boundary-layer and synoptic-scale forcing contributing to jet occurrence. This study being conducted by Dr. Claudia Walters at the University of Michigan-Dearborn, Dr. Julie Winkler at Michigan State University and Dr. Sharon Zhong at Michigan State University will address two substantial gaps in our knowledge of low-level jets. One goal is to better understand the characteristics, causes, and impacts of N-LLJs, which have received little attention to date by the atmospheric science community. The specific objectives of this first goal are to 1) characterize the large-scale synoptic environment in which N-LLJs form, 2) assess the three-dimensional structure of N-LLJs, 3) evaluate the potential forcing mechanisms for N-LLJs, 4) investigate the impacts of N-LLJs on local/regional weather and climate, and 5) improve the understanding of the climatological characteristics of N-LLJs including their interannual variation. The second goal is to evaluate the relative contribution of boundary-layer versus synoptic-scale forcing to S-LLJ occurrence. The specific objectives of this goal are to 1) assess the geographic variations in the relative frequency of boundary-layer versus synoptically-forced S-LLJs, 2) evaluate the contrasting influence of the different types of S-LLJs on nocturnal precipitation, and 3) depict the interannual variability of the different S-LLJs. These objectives will be addressed using a combination of mesoscale numerical modeling and climatological analysis of surface and upper-air observations and regional reanalysis products. The outcomes of the research will directly benefit both short-term and seasonal operational weather forecasting and provide a baseline for evaluating potential future changes of low-level jets in a perturbed climate. In addition, better knowledge of forcing mechanisms can lead to improvements in regional and global climate model simulations of low-level jets and their validation. Furthermore, the results will contribute to improved wind energy assessment and water resources management, both of which have broad societal impacts. In addition to the scientific advancements, this research will also provide training to a diverse pool of undergraduate and graduate students in climate data analysis and numerical modeling, produce educational outreach materials for underrepresented and underserved high school students, and develop a web-based outreach resource on low-level jets for the operational weather forecasting community.

该奖项是根据2009年美国复苏和再投资法案(公法111-5)资助的。低空急流是对流层下部快速移动的气流。北风低空急流(N-LLJ)和南风低空急流(S-LLJ)都频繁出现在美国中部，对地区天气气候、降水和水资源以及风能产生重大影响。低空急流的成因是复杂的，边界层强迫和天气尺度强迫共同促成了急流的发生。这项由密歇根大学迪尔伯恩分校的克劳迪娅·沃尔特斯博士、密歇根州立大学的朱莉·温克勒博士和密歇根州立大学的钟莎伦博士进行的这项研究，将解决我们对低空喷流知识的两个重大空白。一个目标是更好地了解N-LLJ的特征、原因和影响，到目前为止，大气科学界对N-LLJ的关注很少。第一个目标的具体目标是1)描述N-LLJ形成的大尺度天气环境，2)评估N-LLJ的三维结构，3)评估N-LLJ的潜在强迫机制，4)调查N-LLJ对当地/区域天气和气候的影响，5)增进对N-LLJ的气候学特征，包括其年际变化的了解。第二个目标是评估边界层强迫与天气尺度强迫对S-低空急流发生的相对贡献。这一目标的具体目标是：1)评估边界层相对频率与强迫S低空急流的相对频率的地理变化；2)评估不同类型S低空急流对夜间降水的对比影响；3)刻画不同S低空急流的年际变率。将结合地面和高空观测的中尺度数值模拟和气候学分析以及区域再分析产品来处理这些目标。研究结果将直接有利于短期和季节性业务天气预报，并为评估扰动气候下低空急流未来可能的变化提供基线。此外，更好地了解强迫机制可以改进区域和全球气候模型对低空急流的模拟及其验证。此外，结果将有助于改善风能评估和水资源管理，这两者都具有广泛的社会影响。除科学进展外，这项研究还将为不同的本科生和研究生提供气候数据分析和数值模拟方面的培训，为人数不足和服务不足的高中生编写教育宣传材料，并为业务天气预报社区开发一个关于低空喷气式飞机的网上宣传资源。