Polar ozone hole makes big comeback
30 August 2005
Envisat's Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) routinely monitors ozone levels on a global basis, continuing a dataset of measurements stretching back to mid-1995, previously made by the Global Ozone Monitoring Experiment (GOME) aboard the earlier ESA spacecraft ERS-2.
As part of the PROMOTE service,
the satellite results are combined with meteorological data and wind field
models so that robust ozone and ultraviolet forecasts can be made. In a first
for ESA, these results are being used by the World Meteorological Organisation
(WMO) to compile their regularly-updated Antarctic Ozone Bulletin.
The stratospheric ozone layer
that protects life on Earth from harmful ultraviolet (UV) radiation is
vulnerable to the presence of certain chemicals in the atmosphere such as
chlorine, originating from man-made pollutants like chlorofluorocarbons (CFCs).
As the polar spring arrives, the
combination of returning sunlight and the presence of polar stratospheric clouds
leads to splitting of chlorine into highly ozone-reactive radicals that break
ozone down into individual oxygen molecules. A single molecule of chlorine has
the potential to break down thousands of molecules of ozone.
Developing out of the successful precursor Tropospheric Emission Monitoring Information Service (TEMIS), PROMOTE is a portfolio of information services covering the atmosphere part of the Earth System, operating as part of ESA's initial Services Element of Global Monitoring for Environment and Security (GMES). This is a joint initiative between ESA and the European Commission to combine all available ground- and space-based information sources and develop a global environmental monitoring capability for Europe.