Editing Ozone layer (section)

==Distribution in the stratosphere==
{{More citations needed section|date=February 2013}}
[[File:Atmosphere20Layers 2018.jpg|thumb|Ozone layer within Earth's atmosphere by altitude]]

The thickness of the ozone layer varies worldwide and is generally thinner near the equator and thicker near the poles.<ref name="APH">{{cite book |title=Global Warming: The Effect Of Ozone Depletion |author=Tabin, Shagoon |publisher=APH Publishing |year=2008 |isbn=9788131303962 |page=194 |url=https://books.google.com/books?id=QFBmUu1lwzAC |access-date=January 12, 2016}}</ref> Thickness refers to how much ozone is in a column over a given area and varies from season to season. The reasons for these variations are due to atmospheric circulation patterns and solar intensity.<ref>{{cite web |title=Nasa Ozone Watch: Ozone facts |website=ozonewatch.gsfc.nasa.gov |url=https://ozonewatch.gsfc.nasa.gov/facts/SH.html |access-date=September 16, 2021}}</ref>

The ozone layer ends gradually, but in general its upper limit is where air becomes too thin for UV light to generate much ozone, and its lower limit is where generated ozone blocks enough UV light to stop most ozone production.

In the [[homosphere]], wind-driven movement is more important than relative gas weight. The majority of ozone is produced over the [[tropics]] and is transported toward the poles by stratospheric wind patterns. In the northern hemisphere these patterns, known as the [[Brewer–Dobson circulation]], make the ozone layer thickest in the spring and thinnest in the fall.<ref name="APH"/> When ozone is produced by solar UV radiation in the tropics, it is done so by circulation lifting ozone-poor air out of the troposphere and into the stratosphere where the sun [[photolyzes]] oxygen molecules and turns them into ozone. Then, the ozone-rich air is carried to higher latitudes and drops into lower layers of the atmosphere.<ref name="APH"/>

Research has found that the ozone levels in the United States are highest in the spring months of April and May and lowest in October. While the total amount of ozone increases moving from the tropics to higher latitudes, the concentrations are greater in high northern latitudes than in high southern latitudes, with spring ozone columns in high northern latitudes occasionally exceeding 600 DU and averaging 450 DU whereas 400 DU constituted a usual maximum in the Antarctic before anthropogenic ozone depletion. This difference occurred naturally because of the weaker polar vortex and stronger Brewer–Dobson circulation in the northern hemisphere owing to that hemisphere's large mountain ranges and greater contrasts between land and ocean temperatures.<ref>{{cite journal |author=Douglass |first1=Anne R. |last2=Newman |first2=Paul A. |last3=Solomon |first3=Susan |title=The Antarctic ozone hole: An update |journal=Physics Today |year=2014 |volume=67 |issue=7 |pages=42–48 |publisher=American Institute of Physics |bibcode=2014PhT....67g..42D |doi=10.1063/PT.3.2449 |hdl=1721.1/99159 |hdl-access=free |url=https://physicstoday.scitation.org/doi/pdf/10.1063/PT.3.2449}}</ref> The difference between high northern and southern latitudes has increased since the 1970s due to the [[ozone hole]] phenomenon.<ref name="APH"/> The highest amounts of ozone are found over the Arctic during the spring months of March and April, but the Antarctic has the lowest amounts of ozone during the summer months of September and October,

[[File:Nimbus ozone Brewer-Dobson circulation.jpg|thumb|300px|Brewer–Dobson circulation in the ozone layer]]