Stratosphere-Troposphere Coupling and Climate Change

On intraseasonal time scales, variations in the strength of the northern stratospheric polar vortex appear to couple downward to affect climate and weather. In the Southern Hemisphere, observations and modeling studies show that springtime ozone depletion effects Antarctic climate that lasts into the summer. Presumably, sustained shifts in the strengths of the stratospheric polar vortices would have similar effects on surface climate. However, it is not known how the stratosphere will evolve as climate changes—models do not agree. I will present an overview of the issues involved, and SPARC's effort to organize modeling efforts to address this issue.