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A GUV multifilter radiometer was set up at Marambio, 64° S 56° W, Antarctica, in 2017. The instrument measures continuously ultraviolet (UV) radiation, visible (VIS) radiation and photosynthetically active radiation (PAR). The measurements are designed for providing high quality long-term time series which can be used to assess the impact of global climate change in the Antarctic region. The quality assurance includes regular absolute calibrations and solar comparisons performed at the site and at Sodankylä, Finland. The actual measurements continue the time series measured at Marambio with NILU-UV radiometers during 2000–2010 as part of the Antarctic NILU-UV network. They are optimal for assessing the effects of the ongoing stratospheric ozone recovery on the ecosystem as the data products include information on radiation at various wavelengths ranging from UV to VIS so that changes on biologically effective radiation due to ozone can be separated from those due to other factors. The final data products are total ozone, PAR, VIS radiation at 555 nm, UV index, UV irradiance at 5 channels, UVB and UVA dose rate/daily dose, and biologically weighted UV dose rate/daily dose, including 10 different action spectra. The data from the last five days and the daily maximum UV index time series are plotted and updated daily on the web page fmiarc.fmi.fi/sub_sites/GUVant/. The first two years of UV measurements were very different in terms of the results: The monthly average of daily maximum UVB dose rates were clearly higher in 2018 than in 2017 during the period from October to December. The largest difference was observed in October, when the average of daily maximum UVB dose rates was 7.6 kWm−2 and 10.2 kWm−2 in 2017 and 2018, respectively. The monthly averages were close to each other for all the three months in 2018, while in 2017 the monthly average of October was lower than those of November and December. VIS and PAR time series show that daily maxima in 2018–2019 exceed those in 2017–2018 during the late spring and the summer (mid-November–January). The studied dataset is freely accessible at https://doi.org/10.5281/zenodo.3553634 (Lakkala et al.,2019). [ABSTRACT FROM AUTHOR]

Solar ultraviolet (UV) irradiances were measured with NILU-UV multichannel radiometers at Ushuaia (54°S) and Marambio (64°S) between 2000 and 2013. The measurements were part of the Antarctic NILU-UV network, which was started in cooperation between Spain, Argentina and Finland. The erythemally weighted UV irradiance time series of both stations were analysed for the first time. The quality assurance procedures included a travelling reference instrument to transfer the irradiance scale to the stations. The time series were homogenized and high quality measurements were available for the period 2000-2010. During this period UV indices of 11 or more were measured on 5 and 35 days at Marambio and Ushuaia, respectively. At Marambio, the peak daily maximum UV index of 12 and daily doses of around 7kJm-2 were measured in November 2007. The highest UV daily doses at both stations were typically around 6kJm-2 and occurred when the stations were inside the polar vortex, resulting in very low total ozone amount. At both stations, daily doses in late November could even exceed those in the summer. At Marambio, in some years, also daily doses in October can be as high as those during the summer. At Ushuaia, the peak daily maximum UV index of 13 was measured twice: in November 2003 and 2009. Also during those days, the station of Ushuaia was inside the polar vortex. [ABSTRACT FROM AUTHOR]

Brewer total ozone column measurements started in Sodankylä in May 1988, 9 months after the signing of The Montreal Protocol. The Brewer instrument has been well maintained and frequently calibrated since then to produce a high-quality ozone time series now spanning more than 25 years. The data have now been uniformly reprocessed between 1988 and 2014. The quality of the data has been assured by automatic data rejection rules as well as by manual checking. Daily mean values calculated from the highestquality direct sun measurements are available 77% of time with up to 75 measurements per day on clear days. Zenith sky measurements fill another 14% of the time series and winter months are sparsely covered by moon measurements. The time series provides information to survey the evolution of Arctic ozone layer and can be used as a reference point for assessing other total ozone column measurement practices. [ABSTRACT FROM AUTHOR]

Brewer total ozone column measurements started in Sodankylä in May 1988, 9 months after the signing of The Montreal Protocol. The Brewer instrument has been well maintained and frequently calibrated since then to produce a high-quality ozone time series now spanning more than 25 years. The data have now been uniformly reprocessed between 1988 and 2014. The quality of the data has been assured by automatic data rejection rules as well as by manual checking. Daily mean values calculated from the highestquality direct sun measurements are available 77 % of time with up to 75 measurements per day on clear days. Zenith sky measurements fill another 14 % of the time series and winter months are sparsely covered by moon measurements. The time series provides information to survey the evolution of Arctic ozone layer and can be used as a reference point for assessing other total ozone column measurement practices. [ABSTRACT FROM AUTHOR]