Long Term Trend in the Middle Atmosphere Temperature

The middle atmosphere is the place where the largest changes of anthropogenic origin have been observed in the last decades. The development of the Antarctic Ozone hole is the best known of such changes, but it is shown in this review that large changes are observed in the temperature, partly under the influence of the ozone depletion, and partly as a consequence of the increase in the concentration of greenhouse gases, mainly CO₂, CH₄ and H₂O. The temperature changes are compared with what is expected from the measured changes in atmospheric composition using different models. In both the stratosphere and the mesosphere, the temperature has decreased faster than predicted by any model. The fact that whereas the temperature is increasing in the troposphere, a cooling is already observed just above the tropopause, and this could be a major source of perturbation in the wave propagation between the two layers, and have an impact on the general circulation and therefore on the climate.