Effects of ozone cooling in the tropical lower stratosphere and upper troposphere

Abstract

In this paper, we examine the tropical lower stratosphere and upper troposphere and elucidate the key role of ozone changes in driving temperature trends in this region. We use a radiative fixed dynamical heating model to show that the effects of tropical ozone decreases at 70 hPa and lower pressures can lead to significant cooling not only at stratospheric levels, but also in the "sub-stratosphere/upper tropospheric" region around 150-70 hPa. The impact of stratospheric ozone depletion on upper tropospheric temperatures stems from reduced longwave emission from above. The results provide a possible explanation for the long-standing discrepancy between modeled and measured temperature trends in the uppermost tropical troposphere and can explain the latitudinal near-homogeneity of recent stratospheric temperature trends. Copyright 2007 by the American Geophysical Union.