Jahresbericht 08 - PMOD/WRC

20
Scientific Research Activities
Simulations of the Climate, Chemistry, and Ozone Changes during 1960-2006
Eugene Rozanov and Tatiana Egorova
With CCM SOCOL v2.0 we simulated the evolution of
the climate, chemistry and ozone during 1960-2006.
The results of the experiments have been submitted
for the second phase of the Chemistry-Climate Models
Validation campaign (CCMval-2).
The CCMval-2 campaign was organized to provide necessary
data for the next WMO Ozone depletion report. One
of the CCMval-2 requests was to simulate climate, chemistry
and ozone trends in the recent past (1960-2006) using
provided sets of the monthly mean natural and anthropogenic
forcings: sea surface temperature, sea ice concentration,
greenhouse gases, ozone destroying
substances, sources of carbon monoxide and reactive nitrogen
oxides, solar spectral irradiance, stratospheric sulfate
aerosol, and stratospheric quasi-biennial oscillation.
We have carried out this experiment with CCM SOCOL
v2.0 (Schraner et al., 2008) in ensemble mode (3 ensemble
members) and many requested atmospheric quantities
were uploaded to the CCMval-2 ftp-server.
To illustrate the model performance we have plotted the
zonal mean total inorganic chlorine (Cly) mixing ratio in October
over 80°S averaged over the pressure range 30-50
hPa. This quantity was chosen because the previous version
of CCM SOCOL failed to simulate its magnitude
(Eyring et al., 2006) causing some problems in the simulation
of the total ozone tendencies over the southern highlatitudes.
The results from the CCM SOCOL v2.0 run are
shown in Figure 1. The simulated Cly reveals a steady increase
from 1960 to 1995 and some stabilization due to
limitations in ODS production afterwards. The peak value is
around 2.7 ppbv, which is much closer to the 3.0 ppbv estimated
on the basis of different satellite observations
(Eyring et al., 2006). The relatively small dependence on
the ensemble member should be noted.
Figure 2 illustrates the time evolution of the zonal mean total
ozone from 1960 to 2006 over 80°S in October. In general,
the behavior of total ozone follows the time evolution of Cly,
however, some deviations after the eruption of Pinatubo
(1991-1993) are noticeable. A leveling off of ozone depletion
is reached in the late 1990s, while towards the end of
the record a slight increase in total ozone can be observed,
albeit small and probably not statistically significant. Full
analyses of the results obtained will be conducted by the
scientific community next year.
Cl y (ppbv)
Total ozone (D.U.)
3.5
3.0
2.5
2.0
1.5
1.0
0.5
300
250
200
150
100
1960 1970 1980 1990 2000 2010
year
Figure 1. Time evolution of the zonal mean October Cly mixing ratio in
the 30-50 hPa layer over 80° S. The results of three ensemble members
are shown in different colors.
1960 1970 1980 1990 2000 2010
year
Figure 2. Time evolution of the zonal mean October Total Column Ozone
over 80° S. The results of three ensemble members are shown in different
colors.
References: Eyring V., Butchart N., Waugh D.W., Akiyoshi H., Austin J.,
Bekki S., Bodeker G.E., Boville B.A., Brühl C.,
Chipperfield M.P., Cordero E., Dameris M., Deushi M.,
Fioletov V.E., Frith S.M., Garcia R.R., Gettelman A.,
Giorgetta M.A., Grewe V., Jourdain L., Kinnison D.E.,
Mancini E., Manzini E., Marchand M., Marsh D.R.,
Nagashima T., Newman P.A., Nielsen J.E., Pawson S.,
Pitari G., Plummer D.A., Rozanov E., Schraner M.,
Shepherd T.G., Shibata K., Stolarski R.S., Struthers H.,
Tian W., Yoshiki M., Assessment of temperature, trace
species, and ozone in chemistry-climate model simulations
of the recent past, J. Geophys. Res., 111, D22308,
doi: 10.1029/2006JD007327, 2006.
Schraner M., Rozanov E., Schnadt Poberaj C.,
Kenzelmann P., Fischer A.M., Zubov V., Luo B.P.,
Hoyle C.R., Egorova T., Fueglistaler S., Brönnimann S.,
Schmutz W., Peter T., Technical Note: Chemistry-climate
model SOCOL: version2.0 with improved transport and
chemistry/micro-physics schemes, Atmos. Chem. Phys.,
8, 5957-5974, 2008.