ESA ENVISAT - Record loss of ozone over Arctic

Average Arctic total ozone for the month of March between 1979 and 2011, based on assimilated observations of several satellite instruments: TOMS, SBUV, GOME, SCIAMACHY, OMI, GOME-2.Credits: KNMI

ESA’s Envisat satellite has measured record low levels of ozone over the Euro-Atlantic sector of the northern hemisphere during March.

This record low was caused by unusually strong winds, known as the polar vortex, which isolated the atmospheric mass over the North Pole and prevented it from mixing with air in the mid-latitudes.
This led to very low temperatures and created conditions similar to those that occur every southern hemisphere winter over the Antarctic.

	Arctic temperature field

As March sunlight hit this cold air mass it released chlorine and bromine atoms – ozone-destroying gases that originate from chlorofluorocarbons (CFCs) and break ozone down into individual oxygen molecules – predominantly in the lower stratosphere, around 20 km above the surface.


Ozone is a protective atmospheric layer found at around 25 km altitude that acts as a sunlight filter shielding life on Earth from harmful ultraviolet rays, which can harm marine life and increase the risk of skin cancer and cataracts.
ESA - Observing the Earth - Record loss of ozone over Arctic - images