Seasonal trends in erythemal and carcinogenic ultraviolet radiation at mid-southern latitudes 1989-1991.

A network of solar carcinogenic/erythemal ultraviolet radiometers has been established in New Zealand. Daily integrated irradiances of this biologically harmful ultraviolet radiation for 1989, 1990 and 1991 are reported from radiometers located at Wellington (41 degrees S) and Christchurch (43.5 degrees S) and for 1990 and 1991 from the Auckland (37 degrees S) radiometer. Although the monitoring program has not been running sufficiently long to discern any long-term changes in levels of solar ultraviolet radiation, shorter term trends are apparent, which are attributed to a seasonal cycle in levels of ozone at midlatitudes and changes in atmospheric aerosols.