Composition and Chemistry
The impact of greenhouse gases on past changes in tropospheric ozone
Article first published online: 13 DEC 2012
©2012. American Geophysical Union. All Rights Reserved.
Journal of Geophysical Research: Atmospheres (1984–2012)
Volume 117, Issue D23, 16 December 2012
How to Cite
2012), The impact of greenhouse gases on past changes in tropospheric ozone, J. Geophys. Res., 117, D23304, doi:10.1029/2012JD018293., , , , , , , , and (
- Issue published online: 13 DEC 2012
- Article first published online: 13 DEC 2012
- Manuscript Accepted: 23 OCT 2012
- Manuscript Revised: 22 OCT 2012
- Manuscript Received: 14 JUN 2012
- climate change;
- greenhouse gases;
 The impact of changes in the abundance of greenhouse gases (GHGs) on the evolution of tropospheric ozone (O3) between 1960 and 2005 is examined using a version of the Goddard Earth Observing System chemistry-climate model (GEOS CCM) with a combined troposphere-stratosphere chemical mechanism. Simulations are performed to isolate the relative role of increases in methane (CH4) and stratospheric ozone depleting substances (ODSs) on tropospheric O3. The 1960 to 2005 increases in GHGs (CO2, N2O, CH4, and ODSs) cause increases of around 1–8% in zonal-mean tropospheric O3 in the tropics and northern extratropics, but decreases of 2–4% in most of the southern extratropics. These O3 changes are due primarily to increases in CH4 and ODSs, which cause changes of comparable magnitude but opposite sign. The CH4-related increases in O3are similar in each hemisphere (∼6%), but the ODS-related decreases in the southern extratropics are much larger than in northern extratropics (10% compared to 2%). This results in an interhemispheric difference in the sign of past O3 change. Increases in the other GHGs (CO2 and N2O) and SSTs have only a small impact on the total burden over this period, but do cause zonal variations in the sign of changes in tropical O3 that are coupled to changes in vertical velocities and water vapor.