Steady-state aerosol distributions in the extra-tropical, lower stratosphere and the processes that maintain them
1Department of Mechanical and Materials Engineering, University of Denver, Denver, CO, 80208-0177, USA
2Department of Chemistry, Williams Hall, Kent State University, Kent, OH 44240, USA
3NOAA ESRL CSD, 325 Broadway, Boulder, CO 80305, USA
4CIRPAS/Naval Postgraduate School, Marina, CA 93933, USA
5NASA Ames Research Center, MS 245-5, Moffett Field, CA 94035-1000, USA
6University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
7Department of Chemistry, Room 419 Latimer Hall, University of California, Berkeley, CA 94720-1460, USA
8Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, Ca 91109, USA
9Chemistry and Dynamics Branch, MS 483, NASA Langley Research Center, Hampton, VA 23681, USA
10NOAA ESRL GMD, 325 Broadway, Boulder, CO 80305, USA
Abstract. Measurements of aerosol, N2O and OCS made in the Northern Hemisphere below 21 km altitude following the eruption of Pinatubo are presented and analyzed. After September 1999, the oxidation of OCS and sedimentation of particles in the extra-tropical overworld north of 45 N are found to maintain the aerosol in a steady state. This analysis empirically links precursor gas to aerosol abundance throughout this region. These processes are tracked with age-of-air which offers advantages over tracking as a function of latitude and altitude. In the extra-tropical, lowermost stratosphere, normalized volume distributions appear constant in time after the fall of 1999. Exchange with the troposphere is important in understanding aerosol evolution there. Size distributions of volcanically perturbed aerosol are included to distinguish between volcanic and non-volcanic conditions. This analysis suggests that model failures to correctly predict OCS and aerosol properties below 20 km in the Northern Hemisphere extra tropics result from inadequate descriptions of atmospheric circulation.
Wilson, J. C., Lee, S.-H., Reeves, J. M., Brock, C. A., Jonsson, H. H., Lafleur, B. G., Loewenstein, M., Podolske, J., Atlas, E., Boering, K., Toon, G., Fahey, D., Bui, T. P., Diskin, G., and Moore, F.: Steady-state aerosol distributions in the extra-tropical, lower stratosphere and the processes that maintain them, Atmos. Chem. Phys., 8, 6617-6626, doi:10.5194/acp-8-6617-2008, 2008.