A NOTE ON THE RECENT INCREASE OF SOLAR UV-B RADIATION OVER NORTHERN MIDDLE LATITUDES

In this work we present the results from the analysis of regular solar UV-B spectral measurements obtained at Thessaloniki (40 degrees N) during a period of three years, from November 1990 through November 1993. The results presented here refer to both clear-skies (cloudiness less than or equal to 3/8) as well as to all-skies conditions, and to solar zenith angles of 63 degrees +/-1 degrees. These results support earlier findings of increased solar W-B irradiances, under all-skies conditions, associated with observed ozone decline at the same period. The observed acceleration of the ozone decline-of about 5% per year-during the three-year period resulted to increased solar UV irradiance levels at Thessaloniki by 12.3% per year at 305 nm and 2.7% per year at 325 mn. These figures are slightly modified under all-skies conditions, and they are in agreement with findings reported independently by other scientists.