Analyses of Large-scale Extratropical Climate Variability and Change

大范围温带气候变率和变化分析

• 批准号: 1343080
• 负责人: David Thompson
• 金额: $ 73.86万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-02-01 至 2018-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1343080&HistoricalAwards=false
• 关键词: Analyses; Large; scale; Extratropical; Climate

This project considers the atmospheric circulation in middle and high latitudes of the Northern and Southern Hemisphere, regions referred to as the extratropics. The project has two components, one of which is to improve understanding of the internal variability of the extratropical circulation, and the other is to examine the processes through which thermal forcing drives externally forced north-south shifts in the extratropical storm tracks and their associated eddy fluxes (which occur in part through the air movements associated with frontal weather systems). Research in the first component is based on the premise that large-scale variability in the extratropical flow arises in the context of two primary types of structures: 1) those that dominate the variance of zonal-mean kinetic energy and the conversion between eddy and zonal-mean kinetic energy (which occurs through eddy momentum fluxes); and 2) those that dominate the variance in eddy potential energy and the conversion between zonal-mean and eddy potential energy (which occurs through eddy heat fluxes). In the Southern Hemisphere (SH), which would be the focus of research in the first component, the structure that dominates variance of zonal-mean kinetic energy is the well-known Southern Annular Mode (SAM), which constitutes a north-south shift of the jet stream and accompanying storm track. Research in the second component seeks to understand how the extratropical circulation responds to a variety of external forcings including the depletion of stratospheric ozone (the "ozone hole"), reductions in Arctic snow cover and sea ice extent, increases in greenhouse gases, and solar irradiance. The research addresses the fundamental dynamics which govern the response of jet streams and their attendant storm tracks using simplified atmospheric circulation models, guided by the hypothesis that key aspects of the response can be understood through a diffusive framework in which eddy fluxes of heat and potential vorticity shift to match, in a down-gradient sense, the changes in their respective mean gradients.The work has broader impacts due to the importance of the fundamental dynamics addressed in the project for understanding and predicting the sensible weather and climate experienced at the Earth's surface. In addition, the work will support and train two graduate students from underrepresented groups, thereby broadening participation in the sciences and contributing to the development of the workforce in this research area.

该项目考虑了北半球和南半球中部和高纬度地区的大气循环，被称为室外。该项目有两个组成部分，其中之一是提高对驱动着热带循环的内部变异性的理解，另一个是要检查热强迫驱动驱动的过程，该过程驱动了驱动的驱动到驱动的倾向性风暴轨迹及其相关的涡流中的北 - 南北变化（通过与额叶天气相关的空气流动发生在一部分中）。第一个组成部分的研究是基于以下前提：在两种主要结构的背景下，出现了驱动气流的大规模可变性：1）占主导地位的层均动能的方差以及涡流和Zonal-Mean-Mean-Mean-Mean-Mean-Mean动能之间的差异（这是通过涡流动量磁通发生的）; 2）那些主导涡流能量方差以及区域均值和涡流势能之间的转化（通过涡质热通量发生的）。在南半球（SH）（SH）中，这将是第一个组成部分的研究重点，占主导地位的区域运动能量的结构是众所周知的南环模式（SAM），它构成了喷气流的南北转移，并伴随着风暴轨迹。 第二部分中的研究试图了解如何对各种外部强迫做出反应，包括耗尽平流层臭氧（“臭氧孔”），北极雪覆盖和海冰范围的减少，温室气体的增加以及太阳辐照度。 该研究探讨了使用简化的大气循环模型来控制喷气流及其随之而来的风暴轨迹的基本动力学，这是基于以下假说，即可以通过一个扩散的框架来理解响应的关键方面，而散热的涡流和潜在的涡度涡流的涡流变化，而在基金上的变化，其范围的变化是在其范围内的变化，其范围的变化是在其范围内的范围变化。理解和预测地球表面上明智的天气和气候的项目。 此外，这项工作将支持并培训来自代表性不足的团体的两名研究生，从而扩大了对科学的参与，并为劳动力在该研究领域的发展做出了贡献。

项目成果

On the Observed Relationships between Wintertime Variability in Kuroshio–Oyashio Extension Sea Surface Temperatures and the Atmospheric Circulation over the North Pacific

• DOI: 10.1175/jcli-d-17-0343.1
• 发表时间: 2018-05
• 期刊: Journal of Climate
• 影响因子: 4.9
• 作者: Samantha M. Wills;D. Thompson