2011- The Year of Two Ozone Holes

As usual The 2011 Ozone Hole formed over Antarctica but unexpectedly an Ozone Hole also formed over The Arctic.

The 2011 Antarctic Ozone Hole is now over. The Ozone Hole began to form in mid August, and by mid September reached it's largest size of 26 million square kilometers on September 12,2011 larger than the average for the last decade and remained near this size into early October according to data from The British Antarctic Survey and NASA. The lowest concentration of ozone in the southern stratosphere—that is, the deepest “hole”—occurred on October 8, 2011 when levels descended to 95 Dobson units. Its size from October to mid November was near to or above the record area for the time of year. The hole became more elliptical in mid October and the edge of the ozone hole passed over the tip of South America and the Falkland Islands, but then returned to a more circular form.

In March of 2011 unusually low temperatures in the Arctic ozone layer initiated massive ozone depletion. The 2011 Arctic Ozone Hole occurred over an area considerably smaller than that of the Antarctic Ozone Holes. This is because the Arctic polar vortex, a persistent large-scale cyclone within which the ozone loss takes place, was about 40 percent smaller than a typical Antarctic vortex. While smaller and shorter-lived than its Antarctic counterpart, the Arctic polar vortex is more mobile, often moving over densely populated northern regions. Decreases in overhead ozone lead to increases in surface ultraviolet radiation, which are known to have adverse effects on humans and other life forms. Read more.