Indicator: A-12 Trend in the area of the ozone hole
Data
Total ozone levels over the southern hemisphere in spring (October 1-15 averages) for 15 years, based on NASA TOMS satellite data.
Images reproduced for every second year from 1980 to 1998 (except 1994 which is missing) and then every year
Source: CSIRO Atmospheric Research; Data NASA GSFC Code 916
Maximum ozone hole area using a 15-day moving average during the ozone hole season
Source: CSIRO Atmospheric Research; Data NASA GSFC Code 916
What the data mean
Southern hemisphere ozone data for 1980 to 2004 show progressive ozone losses over Antarctica. The size of the hole has been fairly constant since the last 1990s but there was a significant decrease in area in 2002. The area of the ozone hole area returned to the more recent higher levels in 2003 and 2004. The 2002 reduction may have been a response to unusual meteorological conditions in the stratosphere.
Data Limitations
Nil known.
Issues for which this is an indicator and why
Atmosphere — Stratospheric ozone - General stratospheric ozone
The largest ozone depletions have occurred over Antarctica. The hole is the region, the so-called ‘ozone hole’ is defined where total ozone levels are less than 220 Dobson units. The cause of ozone depletion from the 1980s has been the steady accumulation of stratospheric chlorine and bromine compounds. This is particularly the case over Antarctica in spring because of the presence of ice nuclei (polar stratospheric clouds) and weak Antarctica sunlight, which provide a very efficient mechanism for ozone depletion. Trends in the size of the ozone hole is a direct measure of this pressure.
Other indicators for this issue:
- A-10 stratospheric chlorine from the major ozone-depleting substances
- A-11 Summer mean total ozone column
- A-13 Surface ultraviolet radiation in Australia
- A-14 Consumption of ozone-depleting substances - Australian consumption of ozone-depleting substances
- A-15 Skin melanoma rates
Australian Antarctic Territory — Environment - Atmosphere, climate and oceans
The largest ozone depletions have occurred over Antarctica. The hole is the region, the so-called ‘ozone hole’ is defined where total ozone levels are less than 220 Dobson units. The cause of ozone depletion from the 1980s has been the steady accumulation of stratospheric chlorine and bromine compounds. This is particularly the case over Antarctica in spring because of the presence of ice nuclei (polar stratospheric clouds) and weak Antarctica sunlight, which provide a very efficient mechanism for ozone depletion. Trends in the size of the ozone hole is a direct measure of this pressure on the Antarctic continent.
Other indicators for this issue:
- AAT-01 Monthly mean air temperature anomalies at Australian Antarctic stations
- AAT-04 Concentrations of greenhouse gases
- AAT-05 Average deep water temperatures
- AAT-06 Average deep water salinity
- A-01 Annual variation in the Southern Oscillation Index
Further Information
Key
Links to another web site
Links to data in the DRS
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