Nature of cold-air outbreaks in Europe in a warming climate

这个项目的目的是调查北极变暖导致的北极-北大西洋地区的变化如何影响欧洲冷空气爆发的性质和严重程度。冷空气爆发是指极地冷气团进入无冰地区。与冷空气爆发相关的冰冻温度和降雪可能导致严重的旅行中断、死亡和经济损失。例如，2018年2月席卷欧洲大部分地区的严重冷空气爆发，导致旅行混乱，导致英国各地多人死亡，每天给英国经济造成约10亿英镑的损失。北极地区一直在经历气候变暖的巨大变化。自大约40年前有卫星记录以来，9月份夏季融化结束时的北极海冰覆盖面积已经减少了一半。在此期间，北极低层大气变暖的速度比整个地球快两到三倍。研究已经证明了北极的这种放大与欧洲气候和极端天气的变化之间的联系，但涉及的机制仍然缺乏特征。北极变暖导致的北极-北大西洋部分的变化似乎对欧洲冷空气爆发的发生没有太大影响，但人们对它们如何影响其性质和严重程度知之甚少。成功的申请者将使用数值模式来研究北极开阔海洋和边缘冰区面积的增加如何转化为冷空气爆发的大气边界层和云层内的变化。该项目将考虑理想和现实的环境，并将根据现有的观测结果对模型结果提出质疑。该项目与国家大气科学中心的S关于气候和高影响天气的科学计划保持一致。该学生将融入NCAS研究社区。申请者将拥有数学、物理或环境科学学位。如需更多信息，请联系Charles Chemel博士(c.Chemel@leeds.ac.uk)。“

"The aim of this project is to investigate how Arctic-warming induced changes in the Arctic-North Atlantic sector affect the nature and severity of cold-air outbreaks in Europe.Cold-air outbreaks are excursions of cold polar air masses into ice-free regions. Freezing temperatures and snow associated with cold-air outbreaks can cause significant travel disruption, fatalities and economic losses. For instance, the severe cold-air outbreak that spread across much of Europe in February 2018, caused travel chaos and led to several deaths across the UK, and costed the UK economy some £1bn a day.The Arctic region has been experiencing considerable changes in the warming climate. The Arctic sea-ice cover at the end of the melt summer season in September has reduced by half since satellite records began about 40 years ago. During this period, the Arctic lower atmosphere has been warming two to three times faster than the planet as a whole. Studies have demonstrated connections between this Arctic amplification and changes in climate and extreme weather in Europe, but the mechanisms involved remain poorly characterised.Arctic-warming induced changes in the Arctic-North Atlantic sector do not appear to largely affect the occurrence of cold-air outbreaks in Europe, but little is known about how they affect their nature and severity.The successful applicant will use numerical models to examine how the increased open-ocean and marginal ice zone areas in the Arctic translate to changes within the atmospheric boundary layer and cloud layer of cold-air outbreaks. Idealised and realistic settings will be considered and model results will be challenged against existing observations.The project is aligned with the National Centre for Atmospheric Science (NCAS)'s science programme on climate and high impact weather. The student will be integrated within the NCAS research community. Applicants will possess a degree in mathematical, physical or environmental science. For further information, please contact Dr Charles Chemel (c.chemel@leeds.ac.uk)."