Erythemal irradiance at the Magellan’s region and Antarctic ozone hole 1999-2005

Abstract

The most austral zone of the Southern Cone of South America, which is sometimes under the influence of the Antarctic Ozone Hole (AOH), occasionally receives enhanced levels of ultraviolet B radiation (UV-B: 280-320 nm). Ultraviolet erythemal irradiance measurements began in 1999 by the University of Magallanes in Punta Arenas (Lat. 53.0º S; Lon. 70.9º W), Chile, with the installation of four instruments in different locations in the Magallanes region, which is the southernmost region in Chile and the nearest to the Antarctic Continent. Data from Solar Light instruments, the Brewer spectrophotometer (Serial 180) and the Total Ozone Mapping Spectrometer (TOMS) from 1999 to 2005 for the Magellan’s Region is presented in this paper. These data show a significant number of days in 2004 with low ozone concentrations, specifying that recovery of the ozone column at these latitudes is still uncertain. Data of erythemal measurements from the stations that are part of the Magallanes network were analyzed, with extra attention given to the spring-summer period when the activity of the AOH is more intense. On several occasions important decreases down to 20-53% in the total ozone column were observed. Along with these decreases, increased levels of UV-B radiation were observed. When compared to normal daily concentration values of the total ozone, the days with increased UV-B levels reached values between ~50 and ~200% above normal at the different stations.