Warm Arctic-Cold Continents trajectory under global warming and impacts of aerosol-induced atmospheric circulation changes on sea ice

Abstract

The Arctic region is experiencing unprecedented warming at nearly four times the global average rate, which drives significant changes in global atmospheric circulation patterns and extreme weather events, profoundly impacting human societies and ecosystems worldwide. This dissertation aims to investigates the complex interplay between Arctic warming, anthropogenic forcings, and their impacts on regional weather patterns, employing statistical techniques and climate model ensemble analysis. The research reveals three key findings. First, it is demonstrated that while the Warm Arctic-Cold Continents (WACC) pattern persists under 1.5°C and 2.0°C warming scenarios, increased variability in East Asian temperature responses complicates prediction accuracy. Second, CESM1 large ensemble simulations reveal that WACC frequency peaks around 2020 before declining—beginning around 2024 for East Asia and 2039 for North America—coinciding with a northward shift of Arctic cold air boundaries as global warming restricts polar air intrusion. Third, this study shows that anthropogenic aerosols paradoxically contribute to sea ice reduction in the western Chukchi Sea by modifying North Pacific circulation patterns, enhancing northward surface stress in the Bering Strait. This mechanism, acting in concert with greenhouse gas forcing, creates a dipole circulation pattern that accelerates sea ice loss beyond what would be expected from greenhouse gases alone. These findings advance our understanding of Arctic climate dynamics and their global teleconnections, providing insights into the evolution of the WACC pattern and unexpected influence of anthropogenic aerosols on Arctic-midlatitude teleconnection.