the thickness of the ozone layer in the atmosphere varies by
The thickness of the ozone layer -- that is, the total amount of ozone in a column overhead -- varies by a large factor worldwide, being in general smaller near the equator and larger towards the poles. It also varies with season, being in general thickest during the autumn and thinner during the early spring. The reasons for this latitude and seasonal dependence are complicated, which involve in atmospheric circulation patterns as well as solar intensity. But in general, bitterly cold temperatures mixed with sunlight assist in maximum ozone depletion, which occurs in early spring.