A comparison of ozone trends from SME and SBUV satellite observations and model calculations

Trends in the ozone mixing ratio near the stratopause are presented for global observations by the Ultraviolet Spectrometer (UVS) instrument on the Solar Mesosphere Explorer (SME) and the Solar Backscatter Ultraviolet Instrument (SBUV) on NIMBUS‐7. The June, September, and January data are separately analyzed for trends as a function of latitude over the 1982‐1986 period. The SME UVS data indicate trends in the range −0.5±1.3%/yr in ozone for the summer hemisphere at 1.0 mbar for January, June, and for all latitudes in September. The SBUV data show decreases of 2‐5%/yr for all three months. Model calculations of ozone trends at 1.0 mb, including 5%/yr ClX increases, measured solar flux decreases over the 1982‐1986 time period, and measured temperatures, reproduce the SME trends. The solar flux and ClX trends contribute equally to the measured changes at 1.0 mb. The SBUV and UVS data exhibit remarkably similar seasonal and latitudinal variations in ozone trends over the five years. The detailed variations of ozone trends from both data sets are reproduced by photochemical model calculations which include latitude‐dependent NMC temperature trends over the 1982‐1986 period.