Influence of Solar Spectral Variability on Middle Atmospheric Ozone
Aimee W. Merkel1 [aimee.merkel@lasp.colorado.edu], Jerald W. Harder1 Anne K.
Smith2 Daniel R. Marsh2 and Thomas N. Woods1
1
2
Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder
Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, Colorado
The Spectral Irradiance Monitor (SIM) on SORCE measures solar spectral
variability in the 200-2400 nm range, accounting for about 97% of the total solar
irradiance (TSI). SIM monitored the descending phase of solar cycle 23 and is now
continuing observations in the rising phase of cycle 24. The SORCE observations show
3– 5 times more variability in ultraviolet (UV) radiation than predicted by a proxy model.
To estimate the atmospheric response to the solar variability implied by these
observations, quiet sun and active solar reference spectra were created as input into the
Whole Atmosphere Community Climate Model (WACCM). The model output suggests a
very different response in photochemically active species in the stratosphere and
mesosphere than from atmospheric forcing from semi-empirical models of SSI. This
atmospheric structure is commensurate with contemporaneous observations of ozone
from TIMED SABER. These results show the importance of local time when
characterizing solar cycle variability in ozone measurements. We will present updated
analysis that extends into the rising phase of solar cycle 24.