HR: 08:55h
AN: A11A-04    [PDF]
TI: The Solar Cycle Variation of Total Ozone in the TOMS Record: Role of Extratropical Wave Forcing
AU: Soukharev, B
EM: boris_soukharev@hotmail.com
AF: Dept. of Climatology, St. Petersburg State University, 10 linia, 33, St. Petersburg, 199178 Russian Federation
AU: * Hood, L L
EM: lon@lpl.arizona.edu
AF: Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd., Tucson, AZ 85737-0092 United States
AB: The merged global satellite total ozone record is characterized by a decadal variation at low latitudes that is approximately in phase with the 11-year solar cycle. Analyses of ozone profile data (SBUV and SAGE) demonstrate that most of the column ozone solar cycle variation occurs in the lower stratosphere (85% below the 16 hPa level). Further evidence for a significant solar cycle variation in the lower stratosphere is obtained from analyses of NCEP 50 hPa temperature data, which also show a decadal variation in phase with the column ozone variation. One source of long-term variability in the tropics and subtropics is extratropical wave forcing, which is an important driver of the Brewer-Dobson circulation. To investigate possible long-term variability of extratropical wave forcing, daily and monthly mean meridional eddy heat fluxes have been calculated at a series of lower-stratospheric pressure levels over a 24-year period using NCEP reanalysis data. A decadal variation of the low-pass filtered extratropical eddy heat flux is present in the NH at pressure levels ranging from 100 hPa to 20 hPa. A similar, but less regular, decadal variation of the eddy heat flux is present in the SH. When this eddy heat flux record is used together with a simplified model based on the ozone continuity equation, it is found that a decadal variation of column ozone in the tropics can be simulated that is in phase with the observed variation (Hood and Soukharev, J. Atmos. Sci., in press). These results suggest that solar UV induced changes in the wave forcing may be mainly responsible for the solar cycle variation of total ozone. We are currently improving the model to account for seasonal differences in sensitivity of tropical total ozone to extratropical wave forcing. Results of the revised model simulations will be presented.
DE: 0341 Middle atmosphere--constituent transport and chemistry (3334)
DE: 1650 Solar variability
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting