Ship-borne ozone (O 3 ) measurements over the Atlantic Ocean during the period from 1977 to 2002 show that O 3 trends in the northern mid-latitudes are small. In contrast, remarkably large O 3 trends occur at low latitudes and in the Southern Hemisphere, where near-surface O 3 has increased by up to a factor of 2. The likely cause is the substantial increase of anthropogenic emissions of nitrogen oxides (NO x ) associated with energy use in Africa, which has added to NO x from biomass burning and natural sources.

Ozone data measured since 1987 in the 35‐ to 45‐km altitude region by differential absorption laser‐radar (DIAL) at Hohenpeissenberg (47.8°N, 11.0°E) confirm the long‐term ozone decline observed by the satellite‐borne Stratospheric Aerosol and Gas Experiment (SAGE) and Halogen Occultation Experiment (HALOE) instruments, as well as interannual ozone fluctuations. Analysis of the DIAL data indicates that the amplitude of ozone variations related to the 11‐year solar cycle might reach up to 7%, much larger than 4% reported in other studies. Higher ozone values observed in the years 2001 to 2003 might, therefore, be a consequence of the ending solar maximum and not necessarily indicate a beginning recovery of upper stratospheric ozone. Much clearer evidence for a recovery is expected in a few years, near the end of the solar minimum starting now.

Abstract. This study gives an overview of interannual variations of total ozone and 50 hPa temperature.

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