scostep 2010 (stp12) - Leibniz-Institut für Atmosphärenphysik an der ...

STP12 Abstracts
Berlin, 12 - 16 July 2010
SCOSTEP Symposium 2010
The dynamical response of ozone and temperature in the lower stratosphere to the 11year
solar cycle simulated by the CCSR/NIES CCM
Yamashita Yousuke 1 , Sakamoto Kei 2 , Akiyoshi Hideharu 1 , Takahashi Masaaki 3 , Nagashima Tatsuya
1 4
, Zhou L. B.
1 2 3
National Institute for Environmental Studies, All Nippon Airways, Atmosphere and Ocean
Research Institute, University of Tokyo, 4 LAPC & LAOR, Institute of Atmospheric Physics, Chinese
Academy of Sciences
The variation of ultraviolet (UV) radiation with the 11-year solar cycle has been suggested
to affect temperature and ozone in the upper stratosphere [e.g., Chandra and McPeters, 1994;
Marsh et al., 2007]. While, in the lower stratosphere the direct effect of the UV radiation
change with the 11-year solar cycle is considered to be small, and the lower stratospheric
ozone is possibly affected by the solar cycle forcing and the sea surface temperature (SST)
variations through the circulation change [e.g., Kodera and Kuroda, 2002; Austin et al., 2008].
The three dimensional chemistry climate model (CCM) is able to provide better description of
these processes than two dimensional model, and it is especially important for explicit
calculation of the planetary wave propagation in the extratropics. It is useful to perform
sensitivity experiments using a three dimensional CCM to estimate these processes. Here we
show the results which exclude the volcanic eruption, because the CCSR/NIES CCM used in
this study overestimates the effects of the volcanic aerosol, which causes unrealistically large
solar response in the lower stratosphere with the multiple regression analysis. The control run
in this study includes the solar cycle forcing and observed SST and excludes the volcanic
forcing.
The results is that the contribution of the solar cycle forcing to the solar term is about 1%
per 100 units F10.7 in ozone concentration solar response and 0.2 K per 100 units F10.7 in
temperature solar response in the lower stratosphere. We show that a change in ozone
transport may be the main factor for the solar signal of ozone concentration in the lower
stratosphere. The magnitudes of ozone and temperature solar responses in the lower
stratosphere are smaller than the observations (about 4% in ozone and 0.5 K in temperature)
which implies that some other factors such as the SST, may be included in results based on
observations.
Another sensitivity experiment with observed SST and fixed solar cycle forcing shows a
small solar response in the lower stratosphere, suggesting that the interannual variability of
the SST could contribute to the solar term in the lower stratosphere through tropospherestratosphere
processes and/or have an effect as an artifact of interference due to the
insufficient period for analysis.