Stratospheric changes influence the climate of the Arctic, through both meteorological effects and direct radiative forcing. The proposers will use a wide variety of model results from chemistry-climate-models (which have good representations of stratospheric dynamics and chemistry) and ocean-atmosphere GCMs, together with observations, to improve understanding of the importance of stratosphere-troposphere coupling, and of how Arctic weather and climate are affected by stratospheric variability. A specific goal of this project is to gain an understanding of the seasonal and regional changes in Arctic weather and climate that can be expected from ozone depletion and recovery in the 21st century with more realistically representation of stratospheric processes in climate models. Mechanisms will be investigated of how stratospheric disturbances penetrate downward to the troposphere and how these disturbances can modify Arctic thermodynamic and dynamic surface processes and ultimately Arctic sea ice concentration. This project will contribute to our understanding of how stratospheric change will affect Arctic climate. Arctic climate impacts not just people living at high latitudes, but delicate ecosystems, with potential feedbacks to global-scale climate change (e.g., methane release from permafrost and changes to the ocean circulation). The project activities are designed to improve understanding of how the Arctic climate will change, using existing model runs and observations. The main scientific impact will be to vertically integrate interdisciplinary Arctic climate change science, from the deep ocean, through surface processes, and up through the troposphere and stratosphere. The project will also contribute to education, and scientific infrastructure. The educational activities include mentoring of a postdoctoral research scientist and providing research projects for undergraduate students for an extended scholarship at NWRA.