Ozone Layer Shrunk, According to ESA

Despite news reports that the Artic sea ice is melting, on the other side of the world, the European Space Agency's satellite has found that the ozone hole over Antarctica has shrunk by as much as 30 percent as compared with last year's figures. According to ESA's Envisat satellite, ozone loss this year is only 27.7 million tonnes, about the size of North America, compared with the 49 million tonnes ozone loss last year.

According to scientists, the smaller ozone hole in the South Pole this year may be due to natural variations in temperature and atmospheric dynamics and does not indicate that the ozone hole will continue to shrink in the longer term. Ronald Van Der, senior project scientist at Royal Dutch Meteorological Institute said that the ozone layer's smaller hole this year is not conclusive that the ozone layer is recovering. Van Der further adds that the ozone hole is less centered on the South Pole which allowed it to mix with warmer air unlike in other years. The mixture of the ozone hole with warmer air may have contributed to the shrinking since ozone is depleted at less than -78 degrees Celsius.

Atmospheric mass in the Antarctic continent is cut off from exchanges with mid-latitude air by the polar vortex during winter in the southern hemisphere, when this happens, the Antarctic experiences very low temperatures and during these times, polar stratospheric clouds are formed that contains chlorine. As spring arrives, the sunlight splits the chlorine in the polar stratospheric clouds, the chlorine then turns into highly ozone reactive radicals that break ozone into individual oxygen molecules. According to scientists, just one single molecule of chlorine can potentially break down thousands of molecules of ozone.

The ozone hole was first discovered in 1985 and the depletion is mainly caused by destructive gases such as chlorine and bromine which mainly originates from chlorofluorocarbons (CFCs). Though CFCs have already been banned by the Montreal Protocol in 1987, CFCs have still not vanished from the air but are declining.

The Envisat's Scanning Imaging Absorption Spectrometer for Atmospheric Chartography instrument generates daily global ozone analyses and nine-day ozone forecasts. Envisat can track ozone depletion, its changes and can even localize the ozone hole which enables a fast estimate and forecast of UV radiation. Data from the Envisat's satellite is used by the PROMOTE (PROtocol MOniToring for the GMES (Global Monitoring for Environment and Security) Service Element) consortium for real-time ozone monitoring and forecasting services. SOURCE:

European Space Agency