RBCC-E Huelva 2015 Ozone Brewer

From May 25th to June 5th 2015, the 10th Regional intercomparison campaign of the Brewer Calibration Center Europe (RBCC-E) was held at El Arenosillo atmospheric sounding station of the Instituto Nacional de Técnica Aeroespacial (INTA). This campaign was jointly conduced by COST Action ES1207 EUBREWNET and the Area of Instrumentation and Atmospheric Research of INTA. Twenty one Brewers, 11 singles and 10 double monochromator instruments from eleven countries participated and were calibrated for total column ozone and solar UV irradiance. Every RBCC-E campaign advances 5 our understanding of the Brewer calibrations in general and specifically what areas still require attention. In this 2015 campaign we have introduced a formal approach to characterization of the internal instrumental stray-light, the filter non-linearity and the algorithm for correcting for its effects on the TOC calculations. This work shows a general overview of the ozone comparison, the evaluation of the correction of the spectral stray light effect for the single-monochromator Brewer spectrophotometer, derived from the comparison with a reference double-monochromator Brewer instrument. At the beginning of the campaign, 10 16 out of the 21 participating Brewer instruments agreed within better than ±1%, and 10 instruments agreed within better than ±0.5% considering data with Ozone Slant Column between 100 and 900 DU, which doesn’t require instrumental stray light correction.