The Arctic Ozone Hole



Map of Arctic: showing Ozone column deficit (DU)

adapted from Fig. 5 from Manney et a 2011.

White contour line shows area in which the data was averaged



Research published recently in Nature, carried out by Gloria Manney and a worldwide team of experts on the ozone layer demonstrates the highly variable manner of ozone depletion over the Arctic. This Arctic ozone layer variability has been observed in 2005, 2000 and 1996 but never before to the extent of 2011 which is for the first time described as comparable to the ozone hole over Antarctica.

The team modelled ozone depletion using a comprehensive set of data from a mixture of satellites, lidar, spectrometers and a network of balloon-borne ozone soundings (ozone sondes). 

Ozone deficit during the 26th March 2011 shown on the map to the above is measured in Dobson Units (DU) which is the measure of ozone area density. The region over the Arctic of purple to light blue is the most adversely affected area when compared to an average ozone background within the white contour line. The most shocking statistic to note is that Ozone loss exceeded 80% at altitudes of 18 to 20km.

The conclusions of the research found that an anomalously prolonged cold period over the Arctic, stretching into spring 2011, provided the conditions necessary for extreme stratospheric ozone depletion. In order to understand the processes involved in ozone reduction my next few blogs will introduce the combing factors.