Collaborative Research: Influences of Amplified Arctic Warming on Extreme Weather in Midlatitudes

最近的科学研究已经开始理清北极变暖和极端天气事件频率增加之间的复杂关系。对这种联系的几种机制进行了假设，最近的研究表明，不同的机制可能会因季节和地区而异。这项研究增进了我们对北半球大陆冬季和夏季过去和未来极端天气事件趋势的了解，以及北极快速变暖在推动这些事件的频率和持续性变化方面的作用。评估了气候模型在捕捉这些关系方面的现实性，结果有助于改进模型模拟。极端天气频率的增加已经直接影响到全球数百万人，如果不是数十亿人的话。这一研究项目的结果对规划者、商业领袖和决策者来说是有价值的，以准备应对未来极端天气事件的增加。这项研究建立在与北极变异性和极端冬季天气事件的统计关联相关的先前工作的基础上，在这些工作中，观测数据集被用来建立北极温暖异常事件与北美东部地区严冬天气之间的联系。研究小组将这一方法扩展到：1)来自再分析和气候模型模拟的网格化数据集，允许探索所有北半球中纬度地区的关系；2)冬季和夏季；以及3)历史和未来预测。这项研究将极大地扩展我们对放大的北极变暖(AAW)与极端夏季和冬季天气条件之间的统计联系的知识，这将为正在进行的联系机制研究提供信息。这项研究具体回答了与有效性、可变性、过去和未来的演变、归因、历史模型模拟的现实主义和持久性有关的问题。社会各级决策者迫切需要更好地了解和更准确地预测极端天气的频率、位置和严重程度的变化。这项研究的结果提供并加强了各种外展模式，为决策者提供了有价值和可操作的信息，并创建了可纳入其他研究人员研究的极端天气指数的新数据集。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Recent scientific studies have begun to disentangle the complex relationship between Arctic warming and the increased frequency of extreme weather events. Several mechanisms for this linkage have been hypothesized, and recent studies reveal that different mechanisms can vary by season and region. This research advances our knowledge of trends in past and future extreme weather events during winter and summer over northern hemisphere continents, and the role of rapid Arctic warming in contributing to changes in the frequency and persistence of those events. The realism of climate models in capturing these relationships are assessed, and results aid in improving model simulations. Increased frequency of extreme weather is already directly affecting millions, if not billions, of people across the globe. The results from this research project are valuable to planners, business leaders, and decision-makers in preparing for future increases in extreme weather events.This study builds upon previous work related to Arctic variability and statistical associations with extreme winter weather events in which observational datasets were used to establish a link between episodes of Arctic warm anomalies and severe winter weather at locations in eastern North America. The research team expands this methodology to, 1) gridded data sets from reanalysis and climate model simulations, allowing exploration of relationships across all northern hemisphere midlatitude areas, 2) both winter and summer seasons, and 3) historical and future projections. The study will greatly expand our knowledge of statistical associations between amplified Arctic warming (AAW) to extreme summer and winter weather conditions that will inform ongoing studies of linkage mechanisms. This research specifically answers questions related to validation, variability, past and future evolution, attribution, realism of historical model simulations, and persistence. A better understanding and more accurate prediction of changes in the frequency, location, and severity of weather extremes are urgently needed by decision-makers at all levels of society. Results from this study inform and enhance various modes of outreach, provide valuable and actionable information to decision-makers, and create new data sets of extreme weather indices that can be incorporated into studies by other investigators.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.