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°N) during a period of three years, from November 1990 through November 1993. The results presented here refer to both clear‐skies (cloudiness ≤3/8) as well as to all‐skies conditions, and to solar zenith angles of 63°±1°. These results support earlier findings of increased solar UV‐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 nm. These figures are slightly modified under all‐skies conditions, and they are in agreement with findings reported independently by other scientists.