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The ozone hole phenomenon, discovered in the 1980s (Chubachi, 1984; Farman et al., 1985) has created the opportunity to study UV-B variations associated to large ozone variations. Typical values of ozone in austral spring at Antarctica should be of about 350-400 DU. However, during ozone hole conditions, very low ozone is observed, and the threshold of 220 DU was defined as the ozone hole condition. Observations by satellites, mainly the Total Ozone Mapping Spectrometer TOMS, have shown the occurrence and the extension of ozone hole (Herman et al., 1993). Very large ozone variations can be observed in austral spring in Antarctic region, between 140 400 DU (Galtier et al., 1994; Chubachi, 1997). It implies in a variation of 65% in a few days. A large UV-B variability is also observed in Antarctic region (Frederick and Snell, 1988; Booth and Madronich, 1994; Frederick and Lubin, 1994; Herman et al., 1996).
Punta Arenas (53.2o S, 70.9o W) is located at the extreme south of South America, and ozone disturbances are best seen in October, when the dynamics of ozone hole make it stretch over the city, and strong depletion is observed during a few days, with ozone reaching values lower than 220 DU (Kirchhoff et al., 1997a). As a result, strong UV-B enhancements are also observed, of about 10 at 297 nm (Kirchhoff et al., 1997b).
The Brazilian Antarctic Station Comandante Ferraz (62o S, 58o W) is located in the King George Island, Southern Shetland, and it shows strong ozone depletion during a large part of spring (Kirchhoff et al., 1997a).
Large UV-B enhancements have been observed (Kirchhoff et al., 2000; Paes Leme et al., 2000).
In this paper, an anticorrelation study ozone X UV-B is made for the month of October 1999, using direct and global UV-B measurements at Punta Arenas, and global UV-B at Ferraz.