Jahresbericht 08 - PMOD/WRC
Jahresbericht 08 - PMOD/WRC
Jahresbericht 08 - PMOD/WRC
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With CCM SOCOL v2.0 we have simulated the evolution<br />
of the climate, chemistry and ozone during 20th<br />
century. The analysis of the land surface temperature<br />
changes revealed that the contribution of solar variability<br />
to climate warming can reach ~50 % in some regions<br />
(e.g., Siberia, Scandinavia, Central USA and<br />
Southern Canada).<br />
We have carried out a 9-member 100-year long transient<br />
ensemble simulation with CCM SOCOL spanning the entire<br />
20th century driven by the prescribed time evolution of<br />
the sea surface temperature, sea ice distribution, volcanic<br />
aerosols, solar spectral irradiance, greenhouse gases,<br />
ozone depleting substances, sources of CO and NOx, land<br />
use, and quasi-biannual oscillation. The model set-up and<br />
some results from this experiment were presented by Fischer<br />
et al. (20<strong>08</strong>). To elucidate the role of changes in solar<br />
activity we have also performed one run without solar irradiance<br />
variability.<br />
Figure 1 illustrates the annual mean land surface temperature<br />
changes calculated as the difference between mean<br />
values over the time periods 1985-1999 and 1901-1915.<br />
The increase of the sea surface temperature is prescribed<br />
from observations, so it is consistent with observations.<br />
The model also simulates the observed warming over land,<br />
which maximizes over high-latitudes and Saudi Arabia.<br />
To estimate the contribution of the solar irradiance variability<br />
we compared temperature changes during 20th century<br />
shown in Figure 1 with the same temperature changes<br />
obtained from the model run carried out with fixed solar<br />
spectral irradiance. The contribution of solar irradiance variability<br />
is shown in Figure 2. The solar spectral irradiance<br />
contribution is rather small over the ocean, because the<br />
ocean temperature was prescribed in both experiments.<br />
Over land the contribution of solar irradiance variability is<br />
noticeable over some geographical locations. Its magnitude<br />
can reach 0.6 K over Siberia, Scandinavia, Central<br />
USA and Canada. Cooling due to solar irradiance variability<br />
is observed over Northern Canada, China and Northern<br />
Africa.<br />
Scientific Research Activities 21<br />
The Response of the Land Surface Temperature to the Solar Irradiance Variability<br />
Eugene Rozanov, Tatiana Egorova, and Werner Schmutz<br />
in collaboration with Andreas Fischer and Stefan Brönnimann IAC ETH, Zurich<br />
References: Fischer A., Schraner M., Rozanov E., Kenzelmann P.,<br />
Schnadt Poberaj C., Brunner D., Lustenberger A.,<br />
Luo B.P., Bodeker G.E., Egorova T., Schmutz W.,<br />
Peter T., Brönnimann S., Interannual-to-decadal variability<br />
of the stratosphere during the 20th century:<br />
ensemble simulations with a chemistry-climate model,<br />
Atmos. Chem. Phys., 8, 7755-7777, 20<strong>08</strong>.<br />
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Figure 1. Changes of the annual mean surface air temperature between<br />
two time periods: 1985-1999 and 1901-1915.<br />
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Figure 2. Contribution of solar irradiance variability to changes in the annual<br />
mean surface air temperature between two time periods: 1985-1999<br />
and 1901-1915.