Ozonesondes Show Record Low Stratospheric Ozone over Summit Station, Greenland in March, 2011

Since February, 2005 the NOAA Earth System Research Laboratory has launched weekly balloon-borne electrochemical concentration cell (ECC) ozonesondes from Summit Station, Greenland (72.6 degrees north, 38.5 degrees west) primarily to monitor stratospheric ozone. The 2011 Arctic polar vortex was reported as being very stable and cold, allowing record stratospheric ozone depletion to occur in the late winter and early spring. This was evident in the ozonesonde record from Summit. The lowest winter and spring time total column in the 6 year record was measured on March 29, 2011 at 259 Dobson Units (DU), approximately 32% lower than the typical 380 DU March average over Summit. Examining 2 km column layer amounts of ozone showed signs of depletion were primarily above 16 km. The 18-20 and 20-22 km layers from March 1 to April 7 each showed the most loss at nearly 50% (about 20 DU) lower than previous years. By April 15, high levels of ozone were observed over Summit with total column up to 470 DU and all layers showing average amounts of ozone for the rest of the spring season.