Calibration and maintenance of Brewer Ozone Spectrophotometers in Sodankylä

The International Ozone Services Inc. (IOS) from Canada, visited the Arctic Space Centre in June 2024.  During the visit, the Center’s two Brewer Ozone Spectrophotometers (Brewers) were calibrated against the Travelling Standard which makes the measurements traceable to the WMO/GAW Brewer Spectrophotometer Ozone Calibration Centre in Toronto. The calibration confirmed that both brewers were still within 0.5% of the Travelling Standard. Calibration and maintenance is carried out every two years as recommended by the WMO.

The first Brewer was installed in Sodankylä in 1988, and a second one was purchased in 2012. From their measurements, total ozone column, spectral ultraviolet (UV) radiation, aerosol optical depth (AOD) at UV wavelengths, and SO2 can be retrieved. Arctic Space Centre’s Brewers are part of the European Brewer Network  (EUBREWNET) from which near real-time data can be downloaded. Data is also contributed to the NDACC and WOUDC data centres. The spectral UV radiation time series is the longest in the European Arctic, and quality controlled data can be downloaded from the European UV Database  (EUVDB).

The Arctic Space Centre has an interesting location in terms of stratospheric climatology, being under the influence of springtime stratospheric ozone depletion. The amplitude of the springtime ozone depletion varies greatly from year to year, and the Brewers are used to monitor this event along with the regular ozone soundings from the research station. Spectral UV radiation measurements are processed to account for various biological effects, providing information on the amount of biologically effective UV radiation reaching the fragile Arctic environment.

Further information:

Kaisa Lakkala, kaisa.lakkala@fmi.fi

Tomi Karppinen, tomi.karppinen@fmi.fi