Collaborative Research: A Teleconnection between the Tropical Madden-Julian Oscillation and Arctic Sudden Stratospheric Warming Events in Warm Climates

合作研究：热带马登-朱利安涛动与温暖气候下北极平流层突然变暖事件之间的遥相关

• 批准号: 1826643
• 负责人: David Randall
• 金额: $ 41.82万
• 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: 2018
• 资助国家: 美国
• 起止时间: 2018-07-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1826643&HistoricalAwards=false
• 关键词: Collaborative; Research; Teleconnection; between; Tropical

The wintertime winds of the Northern Hemisphere stratosphere form a vortex circulating around a cold low pressure cell over the Arctic. Occasionally, perhaps six time in a decade, the vortex experiences a major disruption known as a stratospheric sudden warming (SSW), in which the Arctic stratosphere warms by tens of degrees celsius in just a few days. SSWs are often followed by cold air outbreaks and other forms of severe weather, thus they are of practical as well as scientific interest. Classical studies of SSWs established that the breakdown of the vortex is caused by planetary-scale waves propagating upward and northward into the polar stratosphere. These waves can originate in various ways, and previous work by the PIs and others finds that some SSWs can be linked to the tropical Madden-Julian Oscillation (MJO). The MJO is a broad envelope of cloudiness and convective rainfall that forms over the equatorial Indian Ocean and propagates slowly eastward as far as the central Pacific. Planetary waves generated by the MJO are known to affect weather in middle and high latitudes but their effect on SSWs has not received much attention until recently. The MJO-SSW connection is of particular interest given recent studies suggesting that MJO activity increases when tropical sea surface temperatures (SSTs) increase. The increase in MJO activity suggests greater SSW frequency, but other factors such as changes in the jet streams in a warming climate must also be considered.This project examines the MJO-SSW connection in a hierarchy of models of varying degrees of complexity. The research is enabled by a specialized model configuration which is capable of simulating both the MJO, which is notoriously difficult to capture in current weather and climate models, and SSWs. The model uses superparameterization (SP), a technique pioneered by one of the PIs in which cloud resolving models are embedded in every grid column of a global model (see AGS-0425247). The SP technique is applied in the Community Atmosphere Model (CAM, the atmospheric component model of the Community Earth System Model), used here with enhanced vertical resolution to capture stratospheric dynamics. The work has broader impacts due to the effects of SSWs on surface weather in the Northern Hemisphere. The warming of tropical SSTs raises the prospect of stronger MJO events, and it is of practical interest to understand how stronger events will affect weather regimes over the US and other countries. Moreover, the slow propagation of the MJO offers some hope for extended-range prediction of extreme weather linked to SSWs, thus research on the MJO-SSW connection has implications for operational weather forecasting. The project has educational broader impacts through summer internships supporting undergraduates and local high school students, who are trained in python programming and atmospheric data analysis. The award also provides support and training to two graduate students, thereby providing for the future workforce in this research area.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.

北半球平流层的冬季风形成一个涡流，周围围绕着北极的冷低压电池循环。有时，大概是十年来的六次，涡流会经历重大破坏，称为平流层突然变暖（SSW），在短短几天内，北极平流层在数十次中摄入数十辆。 SSW经常之后是冷空气爆发和其他形式的恶劣天气，因此它们具有实用性和科学兴趣。 SSW的经典研究表明，涡流的分解是由行星尺度波向上和向北传播到极地平流层引起的。 这些波浪可以起源于各种方式，而PIS的先前工作则发现某些SSW可以与热带Madden-Julian振荡（MJO）相关联。 MJO是云彩和对流降雨的广泛信封，在赤道印度洋上形成，并在中太平洋中缓慢地向东传播。 已知MJO产生的行星波会影响中间和高纬度的天气，但直到最近，它们对SSW的影响才受到太多关注。鉴于最近的研究表明，当热带海面温度（SSTS）增加时，MJO-SSW连接特别令人感兴趣。 MJO活性的增加表明SSW频率更高，但还必须考虑其他因素，例如在变暖气候下喷气流的变化。本项目以不同程度的复杂性模型的层次结构研究MJO-SSW连接。这项研究是通过一种专门的模型配置来实现的，该配置能够模拟MJO，众所周知，在当前的天气和气候模型以及SSW中很难捕获。 该模型使用超级参数化（SP），这是一种由一个PI启用的技术，其中云解析模型嵌入了全局模型的每个网格列中（请参见AGS-0425247）。 SP技术应用于社区大气模型（CAM，社区地球系统模型的大气组件模型），此处使用具有增强的垂直分辨率来捕获平流层动力学。由于SSW对北半球表面天气的影响，这项工作具有更大的影响。热带SST的变暖提高了MJO事件更强大的前景，并且了解更强大的事件将如何影响美国和其他国家的天气制度。 此外，MJO的缓慢传播对与SSW相关的极端天气的扩展预测提供了希望，因此对MJO-SSW连接的研究对运营天气预测具有影响。 该项目通过支持本科生和当地高中生的暑期实习，对他们接受了Python编程和大气数据分析的培训。该奖项还为两名研究生提供了支持和培训，从而为该研究领域的未来劳动力提供了支持和培训。该奖项反映了NSF的法定任务，并且使用基金会的知识分子优点和更广泛的审查标准，认为NSF的法定任务值得通过评估。

项目成果

The QBO–MJO Connection: A Possible Role for the SST and ENSO

QBO 与 MJO 的联系：SST 和 ENSO 的可能作用

• DOI: 10.1175/jcli-d-23-0031.1
• 发表时间: 2023
• 期刊: Journal of Climate
• 影响因子: 4.9
• 作者: Randall, David A.;Tziperman, Eli;Branson, Mark D.;Richter, Jadwiga H.;Kang, Wanying
• 通讯作者: Kang, Wanying