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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.

         
         

Isosurfaces of Potential Vorticity

 

Isosurfaces of Potential Vorticity with Height Exaggerated

 

Volume Rendering of Potential Vorticity with Height Exaggerated

         

QuickTime | MPEG

This image shows a satellite view of the earth from space with three isosurfaces of Potential Vorticity mapped over the Northern Hemisphere from day 16 of the simulation. Brighter colors correspond to increasing Potential Vorticity. The animations at right, show the entire 16-day evolution
 

QuickTime | MPEG

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.
 

QuickTime | MPEG

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.

QuickTime |MPEG

This version rotates about a fixed time-step.
         
   
Model  
Model Name:
SEAM
Data  
Time Evolution:
16 days
Supercomputer:
HP SPP2000, 64 processors
CPU Time:
2.5 days
Domain  
Horizontal Resolution:
70 km (~T181)
Grid Points:
22 million
Vertical Resolution:
200 levels
Visualization  
Visualization:

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

Software:
The polygons for the isosurfaces were created with vtk and later ray traced with BMRT's rendrib ray tracer. The volume rendering was performed with NCAR's Volsh software.
Project
Scientists:

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

Date Created:
1998-10-01
Date Catalogued:
2002-08-12
Rights:
© 2002, UCAR, All rights reserved.