ABSTRACT
Networks to measure solar ultraviolet (UV) irradiance have been closely related to observations of atmospheric ozone (O3) that started in 1926/1927 with spectrophotometers developed by the British scientist Gordon Miller Bourne Dobson in Oxford. Model projections of solar radiation reaching the surface over the past and into the future need to take relevant processes of the climate system, their interactions and changes into account. Reconstruction models for past changes of solar UV irradiance were developed and compared for ozone and UV irradiance, and applied to data of individual sites and geographic regions. The penetration of solar radiation into the water column is affected by many factors. UV radiation penetrating into the water column has been found to break down chromophoric dissolved organic matter, making it available for bacterial consumption. This degradation of organic material results in a feedback loop increasing the transmission of solar UV with deleterious consequences for organisms dwelling in the surface layers.
