Upper-stratospheric ozone trends 1979-1998

• Published in: Journal of Geophysical Research 2000-06, Vol.105 (D11), p.14
• Main Authors: Newchurch, M J, Bishop, Lane, Cunnold, Derek, Flynn, Lawrence E, Godin, Sophie, Hollandsworth Frith, Stacey, Hood, Lon, Miller, Alvin J, Oltmans, Sam, Randel, William
• Format: Article
• Language: English
• ISSN: 0148-0227

Extensive analyses of ozone observations between 1978 and 1998 measured by Dobson Umkehr, Stratospheric Aerosol and Gas Experiment (SAGE) I and II, and Solar Backscattered Ultraviolet (SBUV) and (SBUV)/2 indicate continued significant ozone decline throughout the extratropical upper stratosphere from 30-45-km altitude. The maximum annual linear decline of -0.8 +/- 0.2 percent/yr (2 sigma) occurs at 40 km and is well described in terms of a linear decline modulated by the 11-year solar variation. The minimum decline of -0.1 +/- 0.1 percent/yr (2 sigma) occurs at 25 km in midlatitudes, with remarkable symmetry between the Northern and Southern Hemispheres at 40-km altitude. Midlatitude upper-stratospheric zonal trends exhibit significant seasonal variation (+/- 30 percent in the Northern Hemisphere, and +/- 40 percent in the Southern Hemisphere) with the most negative trends of -1.2 percent/yr occurring in the winter. Significant seasonal trends of -0.7 to -0.9 percent/yr occur at 40 km in the tropics between April and September. Subjecting the statistical models used to calculate the ozone trends to intercomparison tests on a variety of common data sets yields results that indicate the standard deviation between trends estimated by 10 different statistical models is less than 0.1 percent/yr in the annual-mean trend for SAGE data and less than 0.2 percent/yr in the most demanding conditions (seasons with irregular, sparse data). (Author)