Collaborative Research: Interactions between Arctic cyclones, atmospheric rivers, and sea ice in a warming climate

由于全球气候变化，北极正在发生巨大的变化，包括北极海冰面积和厚度的大幅减少。过去的研究表明，北极海冰的减少可能会导致地表附近的强风，伴随着更频繁和/或更强烈的风暴。这个项目正在测试这样一个假设，即这种相互作用代表了一种重要但未被认识到的反馈：海冰覆盖面积的减少导致更强的地表风和风暴，更大的地表蒸发，以及更强、更频繁地流入北极的“大气河流”，进而导致海冰加速损失。这项研究的发现将有助于决策者应对北极地区影响该地区人民、生态系统、经济和安全的众多环境挑战。例如，更强的风暴和减少的海冰覆盖可能会导致更强的风浪和更大的海岸侵蚀，影响北极社区。此外，更强的海浪和风暴可能会阻碍扩大北极海上航行的计划。该项目采用了一个原始的视角，通过调查作为一个系统的海冰，湿度和大气/海洋动力学在北极正在进行的气候变化中的相互作用。过去的研究已经调查了某些成分之间的耦合响应，但本研究将通过扩大分析范围，将涉及海冰、旋风、风和水分/降水（包括大气河流）的物理过程的半封闭和部分强化系统纳入其中，从而推进知识。为了实现这些目标，研究人员正在研究来自社区地球系统模式（CESM）大集合、耦合模式比对项目（版本5和6）和极地放大模式比对项目（PAMIP）的存档全球气候模式模拟，并结合使用最新CESM2版本的两组创新模拟实验。他们正在利用这些结果来评估相互作用的物理机制，包括所提出的反馈系统回路，并解决三个主要的研究问题：(1)温带气旋、相关的大气河流和北极风如何通过热量、水分和动量通量影响海冰；(2)海冰如何反过来影响气旋、大气河流和北极风；(3)气候变化如何影响这些反馈过程及其在不同时空尺度上的相对重要性。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。

The Arctic is undergoing a dramatic transformation due to global climate change, including major reductions in the areal coverage and thickness of Arctic sea ice. Past research suggests that Arctic sea ice loss will likely lead to stronger winds near the surface, accompanied by more frequent and/or intense storms. This project is testing the hypothesis that such interactions represent an important but unrecognized feedback: reduced sea ice coverage leading to stronger surface winds and storms, greater surface evaporation, and stronger and more frequent "atmospheric rivers" flowing into the Arctic, leading in turn to accelerated sea ice loss. Discoveries from the study will help decision makers address numerous environmental challenges in the Arctic that affect the region's people, ecosystems, economy, and security. For example, stronger storms and reduced sea ice coverage likely will lead to stronger wind-driven waves and greater coastal erosion affecting Arctic communities. In addition, stronger waves and storms may hinder plans for expanded Arctic marine navigation. This project takes an original perspective by investigating as a system the interactive roles of sea ice, moisture, and atmospheric/oceanic dynamics in the Arctic's ongoing climate transformation. Past studies have investigated coupled responses between certain components, but this research will advance knowledge by broadening the analysis to encompass a semi-enclosed and partially reinforcing system of physical processes involving sea ice, cyclones, wind, and moisture/precipitation (including atmospheric rivers). To achieve these objectives, the researchers are studying archived global climate model simulations from the Community Earth System Model (CESM) Large Ensembles, Coupled Model Intercomparison Project (versions 5 and 6), and Polar Amplification Model Intercomparison Project (PAMIP) in combination with two sets of innovative modeling experiments using the latest CESM2 version. They are using these results to assess the interactive physical mechanisms comprising the proposed feedback system loop and address three overarching research questions: (1) how extratropical cyclones, associated atmospheric rivers, and Arctic winds affect sea ice through heat, moisture, and momentum fluxes; (2) how sea ice in turn affects cyclones, atmospheric rivers, and Arctic winds; and (3) how a changing climate will affect these feedback processes and their relative importance over different spatial and temporal scales.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.