CORRELATIONS BETWEEN TROPOPAUSE HEIGHT AND TOTAL OZONE - IMPLICATIONSFOR LONG-TERM CHANGES

For the central European station of Hohenpeissenberg, averaging of ozo ne profiles grouped by tropopause height shows that the ozone mixing r atio profile in the lower stratosphere shifts up and down with the tro popause. The shift is largest near the tropopause and becomes negligib le above 20 to 25 km. As a consequence a high tropopause is correlated with low total ozone and a low tropopause with high total ozone. Inde pendent of season, total ozone decreases by 16 Dobson units (DU) per k ilometer increase in tropopause height. At Hohenpeissenberg the tropop ause has moved up by 150 +/- 70 m (2 sigma) per decade over the last 3 0 years. If the -16 DU per kilometer correlation between total ozone a nd tropopause height is valid on the timescale of years, it is specula ted that the observed increase in tropopause height could explain abou t 25% of the observed -10 DU per decade decrease of total ozone. This is of the same magnitude as the 30% fraction of midlatitude ozone depl etion which current stratospheric models have difficulty accounting fo r. For Hohenpeissenberg the increase in tropopause height appears to b e correlated with observed tropospheric warming: At 5 km altitude, for example, temperature has increased by 0.7 +/- 0.3 K per decade (2 sig ma) since 1967.