Due to a possible decrease of the total ozone abundance - which is expected to lead to an increase in harmful UV Radiation - the measurement of UV Radiation reaching the surface has become to an important part of climatic observations. So we are interested in possible long-term trends in UV doses related to health and environmental issues.

Further factors controlling the amount of UV-radiation on the surface are the solar elevation, cloud cover and ground reflection (single scattering albedo). Therefore, direct UV irradiance measurements, in combination with a radiative transfer model, allow determination of biologically effective UV doses, albedo and cloud transmission. At UNIS (The University Courses on Svalbard) in Longyearbyen, we use a 5-channel UV irradiance measurement instrument (NILU-UV), combined with a continuously measuring spectrometer. The measurement site in Longyearbyen could be of a special interest because of its high latitude in a polar region (78.2 deg N) and could become an important part in the observations of the middle polar atmosphere.

Examples: "Determination of an effective spectral surface albedo from ground based global and direct UV-irradiance measurements" (A.Kylling, T.Persen, B. Mayer, T.Svenoe),
or "Effect of aerosols on solar UV irradiances during the photochemical activity and solar ultraviolet radiation campaign" (A.Kylling, A.F. Bais, M.Blumthaler, J.Schreder, C.S. Zerefos, E. Kosmidis),