ESS101C
Prof. Jin-Yi Yu
Radiation and Ozone
qOzone Production
q      UV photons are required for ozone production:
q              O2 + UV photon à O + O
q      Below about 20 km, UV photons are absorbed by ozone. Therefore, O2 can be photolyzed only above 20 km. This is why the ozone layer is located in the stratosphere and not near Earth’s surface.
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qOzone Destruction
q      O3 can be split by radiation in the visible-light range:
q              O3 + photon à O2 + O
q      Because many more visible photons than UV photons are available, O3 is photolyzed (ozone destruction) much faster than O2 (ozone production).
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q       Also, O3 can be photolyzed all the way sown to Earth’s surface.