Stratospheric Ozone Depletion

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