Intensity of UV-B Radiation

Intensity of UV-B radiation on the Earth surface is characterised by distinctive daily and yearly pattern depending on the Sun elevation above horizon. The route of the sunlight is dilated through the ozone layer at the lower Sun elevation. Therefore, the harmful radiation is more effectively reduced. The highest values are being recorded in the period of May-August during sunny days, at noon. In May and June 1997, the average ozone value was 8% below normal. Despite this fact, the harmful UV-B radiation flow density exceeded the value of 175 mW per m² which is considered to be high. The UV-B flow density is assessed by DIFFEY biological efficiency spectrum. The limit value of 175 mW per m² was exceeded only during several days from the end of June to the first half of August. It was caused by prevalent cloudy weather conditions.

Total atmospheric ozone level over the territory of Slovakia (1997)

Source: SHMÚ