ALTITUDE DEPENDENCE OF STRATOSPHERIC OZONE TRENDS BASED ON NIMBUS-7 SBUV DATA

A multiple regression statistical model is applied to estimate the alt itude, latitude, and seasonal dependences of stratospheric ozone trend s using 11.5 years of Nimbus 7 SBUV data for the period November 1978 to June 1990. In the upper stratosphere, the derived trends agree in b oth latitude dependence and approximate amplitude with published predi ctions from stratospheric models that consider gas-phase chemical proc esses together with the observed approximately 0.1 ppbV per year incre ase in tropospheric chlorine. The dominant contribution to column ozon e trends occurs in the lower stratosphere where significant negative t rends are present at latitudes >200 in both hemispheres. The observed latitude dependence is qualitatively consistent with model predictions that include the effects of heterogeneous chemical ozone losses on lo wer stratospheric aerosols.