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Recent technology advances have made measurements of UV doses and ozone column amounts with multi-channel filter instruments not only possible, but also an attractive alternative to other more labor-intensive and weather dependent methods. Filter instruments can operate unattended for long periods of time, and it is possible to obtain accurate ozone column amounts even on cloudy days. We present results from extensive comparisons of the performance of several NILU-UV and GUV filter instruments against Dobson and Brewer instruments and the EP-TOMS instrument. The data used in the comparisons are from four different sites where we have had the opportunity to operate more than one type of UV instruments for extended periods of time. The sites include the University of Oslo, Norway, Ny-Alesund, Spitzbergen, Norway, the NASA Goddard Space Flight Center facilities at Wallops Island, VA, and Greenbelt, MD and the University of Alaska, Fairbanks. Our results show that ozone column amounts obtained with current filter-type instruments are just as good as those obtained with the Dobson instrument. The mean difference between NILU-UV and Dobson direct sun measurements were 0.4% ± 1.9% (1σ) in Oslo 2000-2003. The difference between a GUV and the same Dobson was 1.7% ± 1.4% for the same time period. The mean difference between GUV and TOMS in Ny-Alesund 79°N and Oslo 60°N in the period 1996-1999 was < 0.5% ± 3% for days with noon SZA < 80°.
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