Breakdown of the Polar Stratospheric Vortex

The breakdown of the Stratospheric Polar Night Vortex is an atmospheric event that occurs once or twice each year in the polar wintertime stratosphere. As the polar vortex is formed, sharp gradients of potential vorticity at the vortex edge isolate polar air from the air at lower latitudes, producing conditions favorable for wintertime polar ozone depletion. Rossby waves propagating upward from the troposphere along the edge of the Polar Vortex grows exponentially in amplitude, eventually tearing the vortex apart.

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	High Resolution Simulation

The animations depict the flow of the Polar Vortex by visualizing Potential Vorticity (a variable that acts as a tracer) over the 16-day simulation. In the second and succeeding images, the height of the data has been greatly exaggerated to better show the rich vertical structure contained in the vortex. In reality, the vortex is only a few tens of kilometers thick, a pancake-thin region that can extend over much of the Northern Hemisphere.

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A stereographic projection of the Northern Hemisphere from day 16 of the simulation is seen above with the data field exaggerated 200 times in the vertical direction. The animations on the right show the mapping projection as it is warped from satellite view to orthographic, followed by the scaling of the vertical axis.

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This image depicts a volume rendering of the Polar Vortex. The vertical axis is exaggerated 200 times to better show the vertical structure of the vortex. The view is looking down from directly above the North Pole.

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This version rotates about a fixed time-step.

John Clyne, NCAR, SCD
Mark Taylor, NCAR, SCD
Dave Kennison, NCAR, SCD

Lorenzo Polvani, Columbia University
R. Saravanan, NCAR, CGD