Data flow of spectral UV measurements at Sodankylä and Jokioinen

Abstract. We describe the steps that are used at the Finnish Meteorological Institute (FMI) to process spectral ultraviolet (UV) radiation measurements made with its three Brewer spectrophotometers, located in Sodankylä (67° N) and Jokioinen (61° N). The spectrum is measured many times a day, following a pre-programmed schedule. Multiple corrections are made to the data in near real time (dark current, dead time, stray light, noise spikes, temperature, and cosine correction) and quality control is also performed automatically. The Brewers are integrated into the operational control systems at FMI, allowing both quick responses to malfunctions and quick dissemination of the data products. Several data products are produced, including the near-real-time UV index and various daily dosages. The daily doses are calculated each morning for the previous day's data. Once per year the responses of the Brewers are recalculated, and the corrected data are uploaded to the European UV database hosted by FMI.