Simultaneous measurements of ozone and ultraviolet radiation: spring 2000, Punta Arenas, Chile

Total atmospheric column ozone and ultraviolet radiation B (UV-B) were measured at Punta Arenas Chile (lat.53.1oS, long.70.9oW) with a MK-IV (no. 68) Brewer Spectrophotometer between August 1992 and November 2000. This Brewer is the first of its kind installed in southern Chile close to Antarctica. Data were analyzed for the months of August, September and October 2000, a period during which the Antarctic Ozone Hole covered an area of 28.3 million km2, its largest extent so far. A threshold level of 220 Dobson Units (DU) was used to define “Ozone Hole” conditions, which were observed on four occasions that year. On 12 October 2000, ozone values of 170 DU were measured, a 49% decrease compared with the reference mean for October at that latitude. When the Ozone Hole was over Punta Arenas some wavelengths of UV-B increased by more than 20 times compared with similar days when column ozone was normal.