Photo Credit: Kelli-Ann Bliss/NOAA

South Pole staff release a high-altitude balloon, which carries ozone-measurement equipment more than 30 kilometers high in the atmosphere, in mid-September.

Shrinking back

Latest measurements by NOAA at South Pole show smaller ozone hole

The ozone hole that forms each year above the Antarctic was a little smaller in 2013 than in years past, according to a recent news report from the National Oceanic and Atmospheric Administration (NOAA) .

NOAA and the Cooperative Institute for Research in Environmental Sciences (CIRES)   at the University of Colorado-Boulder track trends in seasonal ozone from measurements made by a two-person NOAA crew at the U.S. Antarctic Program's South Pole Station, which hosts the Atmospheric Research Observatory . Earth's ozone layer shields life on the planet’s surface from ultraviolet radiation that can cause skin cancer and damage plants.

In addition, those measurements showed ozone levels in a critical region of the atmosphere did not drop as low as in years past.

The Antarctic ozone hole began making a yearly appearance in the early 1980s, caused by chlorine released from man-made chemicals called chlorofluorocarbons (CFCs). Under the 1987 Montreal Protocol and its later amendments, countries agreed to phase out most ozone-depleting. Chlorine levels at the poles reached a maximum at the beginning of this century and are now on the decline, according to NOAA global observations.

For more about the 2013 ozone hole, see the NOAA press release .

The Atmospheric Research Observatory at the South Pole Station is a National Science Foundation facility used in support of scientific research related to atmospheric phenomena. The majority of the facility is allocated to a long-term research program carried out by NOAA's Global Monitoring Division , which involves measurement of ozone, as well as important trace gases, aerosols, and solar radiation. For more about ARO, see previous article — Fresh air: NOAA observatory takes in the atmosphere at the South Pole.