Arctic Vortex - During winter, stratospheric winds (uppermost atmosphere) tend to form a vortex around the North Pole. These polar clouds lead to chemical reactions that affect the chemical form of chlorine in the stratosphere. In certain chemical forms, chlorine can deplete the ozone layer. Note: This is the standard definition version of the Arctic Vortex animation MPEG. Animator: Susan Twardy (HTSI). Scientist: Paul Newman (NASA/GSFC). Writer: Michael Starobin (HTSI).
