Brewer spectrophotometer total ozone measurements made during the 1998 Middle Atmosphere Nitrogen Trend Assessment (MANTRA) campaign

Abstract Column ozone data collected using a Brewer spectrophotometer at Vanscoy, Saskatchewan during the Middle Atmosphere Nitrogen Trend Assessment (MANTRA) balloon campaign (Strong, this issue) were reduced using an improved analysis algorithm. The retrieved total ozone values are compared with those from other instruments and good agreement was found. The aerosol optical depth has also been calculated using the same set of data and the results are presented. Periods of an increased aerosol optical depth coincide with periods when plumes of smoke from nearby forest fires reached the campaign site.