The ozone hole
The Ozone Hole
The discovery of the ozone hole The British Antarctic Survey has been monitoring for many years, the total column ozone levels at its base at Halley Bay in the antarctica Monitoring data indicate that column ozone levels have been decreasing since 1977 This observation was later confirmed by satellite data (TOMS-Total Ozone Mapping spectrometer) Initially satellite data were assumed to be wrong with values lower than 190DU
The discovery of the ozone hole • The British Antarctic Survey has been monitoring, for many years, the total column ozone levels at its base at Halley Bay in the Antarctica. • Monitoring data indicate that column ozone levels have been decreasing since 1977. • This observation was later confirmed by satellite data (TOMS-Total Ozone Mapping Spectrometer) – Initially satellite data were assumed to be wrong with values lower than 190DU
220 205205 Antarctic ozone minimum (60.9o s) 97 101510 1979-1992 Nimbus 7 TOMS 1996-1994 Meteor 3 TOMS 180 1995 no TOMS in orbit 1996-1998 Earth Probe TOMS g160 154 1003146 1024 140 120 417/100 105 100 930 1980 1985 1990 1995 2000
October ozone hole over antarctic October 13 ⑦ 1979 1991 10020030040000
October ozone hole over Antarctic
Features of the ozone hole Ozone depletion occurs at altitudes between 10 and 20 km If 03 depletion resulted from the ClOx cycle, the depletion would occur at middle and lower latitude and altitudes between 35 and 45 km The ClOx cycle requires atom, but in the polar stratosphere the low sun elevation results in essentially no photodissociation of 02 The above observation could not be explained by the clox destruction mechanism alone Depletion occurs in the Antarctic spring
Features of the ozone hole • Ozone depletion occurs at altitudes between 10 and 20 km – If O3 depletion resulted from the ClOx cycle, the depletion would occur at middle and lower latitude and altitudes between 35 and 45 km. – The ClOx cycle requires O atom, but in the polar stratosphere, the low sun elevation results in essentially no photodissociation of O2. – The above observation could not be explained by the ClOx destruction mechanism alone. • Depletion occurs in the Antarctic spring