Total ozone column (TOC) and effective cloud transmittance (eCLT) from GUV-511 in Oslo, GUV-541 from Andøya/Tromsø, and GUV-541 in Ny-Ålesund.

1h average noon-time values, based on data with 1-minute time resolution.

TOC retrievals from 305/320 nm channel ratio
eCLT retrievals from 340 nm channel 

GUV measurements used in combination with a Radiative Transfer Model

Calibrations based on the FARIN2005-campaign and annual site visits with a travelling reference GUV instrument (https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2007JD009731)

Funding: NILU - Norwegian Institute for Air Research, Norwegian Environment Agency, Norwegian Ministry of health and Care Services