Brewer (1949) and Dobson et al. (1946) proposed that the variation of ozone with latitude might be explained by a slow current (black arrows) moving in the winter hemisphere. Thinking of the distribution of ozone as resulting from a circulation may not be completely accurate. The observed distribution of ozone may simply reflect the altitudes where the ozone cycle can exist and the fact that photodissociation of ozone decreases in winter polar regions due to less available sunlight, allowing ozone to accumulate. Of course the distribution of ozone with altitude and latitude may be affected by the Hadley, mid-latitude, and polar circulation cells driving atmospheric circulation, but the lifetime of ozone is very short. Image from Cordero et al. (2003).