ANSWER: Only 2
Explanation:
- The Northern Hemisphere (Arctic) vortex often contains two low pressure centers, one near Baffin Island, Canada and the other over northeast Siberia.
- Within the Antarctic vortex in the Southern Hemisphere a single low pressure zone tends to be located near the edge of the Ross ice shelf near 160 west longitude.
- When the polar vortex is strong, the Westerlies increase in strength. When the polar cyclone is weak, the general flow pattern across mid-latitudes buckles and significant cold outbreaks occur.
- Ozone depletion occurs within the polar vortices – particularly over the Southern Hemisphere – reaching a maximum depletion in the spring.
- The chemistry of the Antarctic polar vortex has created severe ozone depletion. The nitric acid in polar stratospheric clouds reacts with chlorofluorocarbons to form chlorine, which catalyzes the photochemical destruction of ozone.
