The relationship between solar UV irradiance and total ozone from observations over southern Argentina

Solar ultraviolet (UV) radiation at 300 and 305 nm, measured by a Biospherical Instruments high resolution scanning spectroradiometer at Ushuaia, southern Argentina (55°S, 68°W), as a part of the US National Science Foundation Network for Polar Regions, was compared with total ozone satellite measurements. A statistical relationship between UV and total ozone was derived. On the basis of this relationship, the differences in 300 and 305 nm irradiance between 1979–1983 and 1989–1993 intervals are estimated; for October, the 15% observed decline of total ozone has led to irradiance increases of 80% at 300 nm and 35% at 305 nm. During the days with “ozone hole” conditions, the 300 nm irradiance is as high as it would be at the summer solstice three months later, and is ∼4 times higher than the UV irradiance corresponding to the “normal” ozone condition for early October, as further illustrated for October 1994. Inclusion of the 340 nm cloudy‐dependent predictor is discussed.