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

STP12 Abstracts
Berlin, 12 - 16 July 2010
SCOSTEP Symposium 2010
Sensitivity of the 11-Year Solar Signal in the Atmosphere to Spectral Solar Irradiance
Data and Ozone
Oberländer Sophie 1 , Langematz Ulrike 1 , Matthes Katja 2 , Kubin Anne 1
1 Institut für Meteorologie, Freie Universität Berlin, Germany, 2 Institut für Meteorologie, Freie
Universität Berlin, Germany and Helmholtz-Zentrum Potsdam (GFZ), Germany
The effect of solar variability on the atmospheric radiation budget as
simulated in chemistry climate models (CCMs) strongly depends on the
capability of the broad-band radiation schemes used by the CCMs to account
for the spectral variations of solar irradiance. Another aspect
influencing the amplitude of the simulated solar signal are the spectral
solar fluxes that need to be prescribed at the top of the model
atmosphere. The purpose of this study is to quantify the effects of
prescribing different solar flux data sets on the simulated atmospheric
response, and to compare these to the atmospheric effects of the 11-year
variations in both the solar flux and the ozone, respectively. We will
present results obtained with the FUBRad short-wave radiation
parameterization (Nissen et al., 2007) that was run in offline-mode and as
short-wave (SW) radiation module in the ECHAM5-MESSy (EMAC) CCM. SW
heating rate differences between a minimum (September 1986) and a maximum
phase (November 1989) of the 11-year solar cycle will be compared. They
are calculated using observed spectral solar flux variations from three
different data sets: (a) daily spectral data from UARS/SOLSTICE described
in Lean et al. (2005), (b) spectral solar irradiance reconstructed from
the SATIRE model based on SOHO MDI imaging (Krivova and Solanki, 2005),
and (c) scaled solar variability data derived from SCIAMACHY (Pagaran et
al., 2009). The effect of solar induced ozone variations are taken into
account by prescribing two ozone climatologies for solar maximum and
minimum conditions respectively, taken from offline calculations with a
chemical transport model and the EMAC CCM.