The Causes of Arctic Amplification and its Impact on Mid-latitudes

随着温室气体(GHGs)的增加，北极变暖的速度比世界其他地区快得多--这一现象被称为北极放大(AA)。这种升温加速了海冰的流失，改变了南北温度的分布，影响了中纬度地区的天气和气候。已经提出了许多相互竞争的机制来解释再生障碍性贫血，但关于再生障碍性贫血的影响的研究结果并不确定。这项研究旨在更好地了解北冰洋海冰减少如何影响变暖并对AA做出贡献，以及AA如何在温室气体增加的情况下影响中纬度天气和气候。首席调查人员将进行观测和模式分析，并进行有针对性的模式实验，以实现这一目标。为了量化海冰损失在产生AA和影响中纬度天气和气候方面的作用，首席调查人员将使用NCAR共同体地球系统模式(CESM1)进行新颖的海-气耦合模式实验。这些实验将有助于将由AA加剧的北极变暖和相关的海冰损失造成的影响与由温室气体引起的背景变暖造成的影响区分开来。需要回答的问题是：(1)海冰减少对AA的产生有什么作用？(2)是什么导致海冰融化？(3)AA如何影响高纬度气候？以及(4)AA是否和如何影响中纬度天气和气候？PIS将首先分析月度场，以量化在有和没有海冰丧失的情况下对温室气体增加的平均气候反应(以及相关的AA)。他们将进一步分析日常数据，以量化瞬变天气模式的变化，如大气阻塞、冬季温度和环流异常模式、风暴和海浪活动。这一奖项反映了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。

With increasing greenhouse gases (GHGs), the Arctic has been warming much faster than the rest of the world – a phenomenon known as the Arctic Amplification (AA). This enhanced warming accelerates sea-ice loss and alters the North-South temperature distribution, affecting the mid-latitude weather and climate. Many competing mechanisms have been suggested to explain AA, and findings about the impacts of AA are inconclusive. This research aims to better understand how the Arctic sea-ice loss affects warming and contributes to AA, and how AA affects the mid-latitude weather and climate under increasing GHGs. The principal investigators (PIs) will conduct observational and model analyses, and perform targeted model experiments to address this goal.To quantify the role of sea-ice loss in producing AA and affecting mid-latitude weather and climate, the PIs will perform novel ocean-atmosphere coupled model experiments using the NCAR Community Earth System Model (CESM1). These experiments will help separate the impacts due the enhanced Arctic warming with AA and the associated sea-ice loss from those due to the background warming caused by GHGs. The questions to be answered are: (1) What is the role of sea-ice loss in producing AA?, (2) What causes sea-ice to melt? (3) How does AA affect high-latitude climate?, and (4) Whether and how does AA affect mid-latitude weather and climate? The PIs will first analyze the monthly fields to quantify the mean climate responses to increasing GHGs with and without sea-ice loss (and the associated AA). They will further analyze daily data to quantify changes in transient weather patterns, such as atmospheric blocking, winter temperature and circulation anomaly patterns, storm and wave activities.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.