Continued Investigations of the Structure, Evolution, and Life Cycles of Intraseasonal Fluctuations of the North Pacific Jet Stream

北太平洋急流季节内涨落的结构、演化和生命周期的继续研究

• 批准号: 2055667
• 负责人: Jonathan Martin
• 金额: $ 84.69万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2055667&HistoricalAwards=false
• 关键词: Continued; Investigations; Structure; Evolution; Life

The jet stream over the North Pacific exerts a controlling influence on the procession of winter storms that cross the ocean to make landfall on the US and Canadian coasts. The role of the jet as a conveyor of storms makes it a topic of interest for weather forecasters as the paths and intensities of the storms are sensitive to the various forms of jet variability including extension, retraction and north-south meandering. Perhaps more importantly, jet variations can affect a succession of storms, so the influence of jet fluctuations extends beyond the typical five-day forecast and into the domain of subseasonal prediction. But the underlying dynamics of Pacific jet variations are not well understood and fundamental questions remain as to the mechanisms involved.The Pacific sector is unusual in its combination of middle-latitude jet dynamics, featuring the interplay between the jet and the weather patterns that move along it, and low-latitude influences from the region of deep convection over the warm waters of the western Pacfic. In earlier work one of the Principal Investigators (PIs) used a Linear Inverse Model (LIM) to identify a mechanism through which tropical influences interact with middle-latitude dynamics to produce upper-level circulation anomalies. In the present work the LIM analysis is applied to understand jet fluctuations identified using Self-Organizing Maps (SOMs). The work focuses on the dynamics of transitions from one jet state to another and the consequences of the transitions for downstream weather.The work is of societal as well as scientific interest given its connection to North American weather and relevance to long-range forecasting, as noted above. In addition, the PIs engage in public outreach including a monthly show on Wisconsin Public Radio. The project also provides support and training for two graduate students and two undergraduate summer interns.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

北太平洋上空的急流对穿越海洋登陆美国和加拿大海岸的冬季风暴的进程产生了控制性的影响。 急流作为风暴输送机的作用使其成为天气预报员感兴趣的话题，因为风暴的路径和强度对各种形式的急流变化敏感，包括延伸，收缩和南北蜿蜒。 也许更重要的是，急流变化可以影响一系列风暴，因此急流波动的影响超出了典型的五天预测，进入了亚季节预测领域。 但太平洋急流变化的基本动力学还没有得到很好的理解，有关机制的基本问题仍然存在。太平洋部分是不寻常的，它结合了中纬度急流动力学，其特点是急流和沿着它移动的天气模式之间的相互作用，以及西太平洋温暖沃茨上深对流区域的低纬度影响。 在早期的工作中，一位主要研究员（PI）使用线性逆模型（LIM）来确定热带影响与中纬度动力相互作用产生上层环流异常的机制。 在目前的工作中，LIM分析应用于了解射流波动识别使用自组织映射（SOM）。 这项工作的重点是从一种喷流状态到另一种喷流状态的转变动力学以及这种转变对下游天气的影响，这项工作具有社会和科学意义，因为它与北美天气有关，并与长期预报有关，如上所述。此外，PI参与公共宣传，包括每月在威斯康星州公共广播电台节目。 该项目还为两名研究生和两名本科生暑期实习生提供支持和培训。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

A self organizing maps analysis of north Pacific jet variability

北太平洋急流变化的自组织地图分析

• 发表时间: 2023
• 期刊: Journal of climate
• 影响因子: 4.9
• 作者: Madsen, Maria M.;Martin, Jonathan E.
• 通讯作者: Martin, Jonathan E.

A self-organizing maps analysis of wintertime North Pacific jet stream variability

冬季北太平洋急流变化的自组织地图分析

• 发表时间: 2023
• 期刊: Journal of climate
• 影响因子: 4.9
• 作者: Madsen, Maria M.;Martin, Jonathan E.
• 通讯作者: Martin, Jonathan E.