Ozone measurements in the European Arctic during the ARCTOC 1995 campaign

Abstract

During the first ARCTOC campaign in 1995, ozone was measured continuously at 2 altitudes (40 m asl and 474 m asl) near Ny-Ålesund (Kongsfjord), Svalbard, Norway from 17 April to 8 June. In addition, vertical profiles of ozone and temperature were recorded with balloon sondes at selected dates. A triple event of sudden boundary layer ozone loss (leading to O₃ < 5 ppb) was observed at the beginning of the campaign. The height of the ozone depleted layer ranged from the surface up to 1300m. Additional spectroscopic long-path (DOAS) measurements show a close agreement with the point measurements indicating a well mixed airmass throughout the measurement area. The rate of ozone decrease (dO₃/dt) is considerably higher (on average twice as high) than the subsequent ozone recovery rate. While ozone levels at 40 m and 474 m asl were closely correlated in general, the recovery of ozone after the depletion started 4–6 h earlier at 474 m asl. Reductions in ozone were accompanied by a reduction in stability of the vertical stratification.