Numerical simulation of global variations of temperature, ozone, and trace species in the stratosphere

Abstract

A three‐dimensional dynamical chemical model of the middle atmosphere is used to examine the global response to planetary waves in the middle and high latitudes of the northern hemisphere. The model indicates that larger wave activity in the lower stratosphere at 60°N is correlated with decreasing zonal mean temperatures throughout the tropical and summer hemisphere stratosphere as a result of an induced global‐scale circulation. The tendency of mean ozone is positively correlated with the temperature tendency in the lower stratosphere and negatively correlated in the upper stratosphere. In the upper stratosphere, the anticorrelation of mean ozone and temperature is due primarily to the temperature dependence of many of the reaction rates. The quantitative agreement of the model results with available observations is better when the dependence of the ozone‐temperature relation on the mean ozone amount is removed (by taking the log of ozone) because the model ozone differs from the observed. A model run in which the atmospheric chlorine is removed indicates that the magnitude of the ozone change for a given temperature change can be substantial for modifications in the model photochemistry. Another run tested a more realistic change in which a key reaction rate is modified; the results indicate differences of greater than 10% in the ratio of ozone to temperature changes. With improved measurement capabilities differences of this order may now or soon be detectable. The variations of other chemical species in the model with temperature are also presented.