A network of five stations measuring the solar UV-radiation has been operated for about five years. Data are presented as plotted time-series of monthly and yearly values for the sites. A general climatology can be deduced from these data. Daily and hourly maximum values are shown for each month as indicators of the potential extreme exposure levets. The !arge amma! variation at high  latitudes is easily seen in the data set. This illustrates the importance of rhe  solar  elevation  on  the leve! of the UV-irradiance. Influence of cloud variation and of larger changes in ozone is also detectable. A few examples of the daily variation also show the strong solar elevation dependence of  the  UV-irradiance.

The quantity and unit of the  UV-radiation in this presentation  is CIE-weightecl  irradiance expressed  as MED (minimum erythemal dose), where one MED equals 210 Jm^-2 values have been re- computed to refer to the international intercomparison of broad-band  meters  in Helsinki in 1995.  In the following named  WMO-STUK 1995 scale.

As will be seen there are many sources of error and detailed studies are prevented by the !arge uncertainty connected with these data, Due to the short period of the record and the low accuracy no attempt  to study trends is done.