Abstract. Aerosols play an important role in key atmospheric processes and feature high
spatial and temporal variabilities. This has motivated scientific interest in
the development of networks capable of measuring aerosol properties over
large geographical areas in near-real time. In this work we present and
discuss results of an aerosol optical depth (AOD) algorithm applied to
instruments of the European Brewer Network. This network is comprised of
close to 50 Brewer spectrophotometers, mostly located in Europe and adjacent
areas, although instruments operating at, for example, South America and Australia are
also members. Although we only show results for instruments calibrated by the
Regional Brewer Calibration Center for Europe, the implementation of the AOD
algorithm described is intended to be used by the whole network in the
future. Using data from the Brewer intercomparison campaigns in the years
2013 and 2015, and the period in between, plus comparisons with Cimel
sun photometers and UVPFR instruments, we check the precision, stability, and
uncertainty of the Brewer AOD in the ultraviolet range from 300 to
320 nm. Our results show a precision better than 0.01, an uncertainty
of less than 0.05, and, for well-maintained instruments, a stability similar to that of the ozone measurements. We also discuss future improvements to our
algorithm with respect to the input data, their processing, and the
characterization of the Brewer instruments for the measurement of AOD.
Aerosol optical depth in the European Brewer Network