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.
