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

随着温室气体（GHGs）的增加，北极的变暖速度比世界其他地区快得多——这种现象被称为北极放大（AA）。这种加剧的变暖加速了海冰的损失，改变了南北温度分布，影响了中纬度的天气和气候。人们提出了许多相互竞争的机制来解释AA，但关于AA影响的发现尚无定论。本研究旨在更好地了解北极海冰损失对气候变暖的影响和AA的贡献，以及在温室气体增加的情况下AA对中纬度天气和气候的影响。主要研究人员（pi）将进行观察和模型分析，并进行有针对性的模型实验来实现这一目标。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，pi将使用NCAR社区地球系统模型（CESM1）进行新的海洋-大气耦合模式实验。这些实验将有助于将AA加剧的北极变暖以及相关的海冰损失的影响与温室气体引起的背景变暖的影响区分开来。需要回答的问题是：(1)海冰损失在AA产生中的作用是什么？什么原因导致海冰融化？(3) AA如何影响高纬度气候？(4)机管局是否及如何影响中纬度的天气和气候？pi将首先分析每月的场，以量化有海冰损失和没有海冰损失（以及相关的AA）的温室气体增加的平均气候响应。他们将进一步分析每日数据，量化瞬态天气模式的变化，如大气阻塞、冬季温度和环流异常模式、风暴和波浪活动。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.