AGS-PRF: Antecedent Remote and Local Synoptic Environments Most Conducive to North American Polar/Subtropical Jet Superpositions

急流是一种众所周知的大气现象，但公众普遍不知道在每个半球都有两股主要的急流，即极地急流和副热带急流。 这些喷流通常相隔很远，但在某些情况下可能会出现在同一个地理位置，称为喷流叠加。 这些叠加事件可能与影响非常大的天气事件有关，因此更多地了解其原因和特征对于改善天气预报非常重要。 该奖项资助的研究人员将使用35年的大气数据来识别，分类和分析北美估计的700个叠加事件。 主要的社会影响将是开发和测试一种业务预报产品，该产品将在8-10天的预报范围内对高影响天气事件提供第一警报。 这位早期职业研究员还计划继续他的教育和推广活动，指导一名本科生，并向公众传播科学成果。研究员计划研究喷流叠加事件的主题，其中极地喷流和副热带喷流在最初不同的喷流垂直叠加中相遇。 NCEP CFSR数据集将用于识别北美上空的叠加事件，然后将进行各种分析以回答以下研究问题：1）在急流叠加的整个过程中，极地气旋和热带反气旋PV异常之间的大规模相互作用的性质是什么？ 2)对于每种类型的PV异常相互作用，最有利于产生叠加的前期远程和本地天气环境是什么？叠加对下游中纬度流型有什么影响？ 3)对于每种类型的PV异常相互作用，在喷流叠加事件和“空情况”或PJ和STJ彼此接近但不叠加的情况之间存在什么环境鉴别器？

The jet stream is a well-known atmospheric phenomena, but the public is generally unaware that there are two main jet streams in each hemisphere, the polar jet stream and the subtropical jet stream. These jets are typically separated by a significant distance, but in certain circumstances can end up in the same geographic location, known as a jet stream superposition. These superposition occurrences can be tied to very high-impact weather events, so learning more about their causes and characteristics is important for improving weather forecasts. The researcher funded under this award will use 35 years of atmospheric data to identify, classify, and analyze an estimated 700 superposition events over North America. The main societal impact will be the development and testing of an operational forecast product that would provide a first alert to high-impact weather events in the 8-10 day forecast range. The early career researcher also plans to continue his education and outreach activities by mentoring an undergraduate student and communicating scientific results to the public.The researcher plans to study the topic of jet superposition events, wherein the polar jet and the subtropical jet meet in a vertical superposition of initially distinct jet streams. The NCEP CFSR dataset will be used to identify superposition events over North America and then various analyses will be run to answer the following research questions: 1) What is the nature of the large-scale interactions between polar cyclonic and tropical anticyclonic PV anomalies throughout the production of a jet superposition and does the polar or tropical component consistently dominate those interactions? 2) What are the antecedent remote and local synoptic environments that are most conducive to the production of a superposition for each type of PV anomaly interaction and what influence does a superposition have on the downstream midlatitude flow pattern? 3) What environmental discriminators exist between jet superposition events and "null cases", or instances in which the PJ and STJ closely approach one another but do not superpose, for each type of PV anomaly interaction?