Intercomparison of total ozone data from Nimbus 7 TOMS, the Brewer UV Spectrophotometer and SAOZ UV‐Visible Spectrophotometer at High Latitudes Observatory, Sodankylä

The use of visible spectroscopy makes it possible to measure stratospheric constituents when Solar Zenith Angle (SZA) is as large as 93°. This fact allows the daily measurements of ozone and other species throughout the year at and beyond the latitudes of the polar circle. Because the visible spectroscopy is a new technique in ozone monitoring, it is useful to compare it with the classical uv spectroscopy. At Sodankylä the widely‐used SAOZ uv/visible spectrophotometer (Système d'Analyse et d'Observations Zénithales) and the modem uv spectrophotometer Brewer have been measuring side by side since early 1990. This paper reports the first long‐term intercomparison between the daily total ozone values measured by the SAOZ and the Brewer covering the period from February 1990 to June 1991. As a reference the intercomparison between the Brewer and TOMS (Total Ozone Mapping Spectrometer) instruments from May 1988 to December 1991 is also reported.