1. How is total ozone distributed over the globe?
By Ginny Bister, Robert Metcalfe, Ivan Mariscal

2. Total ozone
Is defined as the sum of all ozone in the atmosphere directly above a certain location
Most ozone resides in he stratospheric ozone layer and only about 10% is distributive throughout the troposphere
Measured in Dobson Units (DU)
Typical values are between 200 and 500 DU 500 DU could form a layer of pure ozone gas at the earths surface with a thickness of 5 millimeters

3. Global distribution Total ozone varies strongly with latitude
Largest values occurring at middle and high latitudes
This is result of ozone production rates from solar ultra-violet radiation
Total ozone values are lowest in the tropics

4. Seasonal distribution
Total ozone varies with season
March and September plots represent the early spring and fall seasons in the northern and southern hemispheres
June and December plots represent the winter and early summer seasons
Total ozone shows a maximum high latitude during spring because of increased ozone transport
Ozone transport is weaker during summer and early fall

5. Seasonal distribution cont.
In the Antarctic, a pronounced minimum in total ozone is observed during the spring.
The minimum is a consequence of an “ozone hole”, which describes the widespread chemical destruction of ozone by ozone depleting substances in spring
Now, the lowest values of total ozone in all seasons are found every spring in the Antarctic

6. Early spring
Early fall
Early summer
Early winter
Early fall
Early summer
Early winter
Early spring

7. Natural variations Patterns change on daily to weekly timescales
Natural air motions blend air between regions of the stratosphere that have high ozone values and those that have low ozone values
Changes in balance of chemical production and loss processes as air moves to and from different locations
This balance is very sensitive to the amount of sunlight in a region