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| Titel |
Evaluation of the ECHAM family radiation codes performance in the representation of the solar signal |
| VerfasserIn |
T. Sukhodolov, E. Rozanov, A. I. Shapiro, J. Anet, C. Cagnazzo, T. Peter, W. Schmutz |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1991-959X
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Model Development ; 7, no. 6 ; Nr. 7, no. 6 (2014-12-03), S.2859-2866 |
| Datensatznummer |
250115788
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| Publikation (Nr.) |
 copernicus.org/gmd-7-2859-2014.pdf |
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| Zusammenfassung |
| Solar radiation is the main source of energy for the Earth's atmosphere and
in many respects defines its composition, photochemistry, temperature profile
and dynamics. The magnitude of the solar irradiance variability strongly
depends on the wavelength, making difficult its representation in climate
models. Due to some deficiencies in the applied radiation codes, several
models fail to show a clear response in middle stratospheric heating rates to
solar spectral irradiance variability; therefore, it is important to evaluate
model performance in this respect before doing multiple runs. In this work we
evaluate the performance of three generations of ECHAM (4, 5 and 6) solar radiation schemes by a comparison with the reference high-resolution libRadtran code. We found that all original ECHAM radiation codes miss almost all solar signals in the heating rates in
the mesosphere. In the stratosphere the two-band ECHAM4 code (E4) has an
almost negligible radiative response to solar irradiance changes and the
six-band ECHAM5 code (E5c) reproduces only about half of the reference
signal, while representation in the ECHAM6 code (E6) is better – it misses a
maximum of about 15% in the upper stratosphere. On the basis of the
comparison results we suggest necessary improvements to the ECHAM family
codes by the inclusion of available parameterizations of the heating rate due
to absorption by oxygen (O2) and ozone (O3). Improvement is
presented for E5c and E6, and both codes, with the introduced
parameterizations, represent the heating rate response to the spectral solar
irradiance variability simulated with libRadtran much better without a
substantial increase in computer time. The suggested parameterizations are
recommended to be applied in the middle-atmosphere version of the ECHAM-5 and
6 models for the study of the solar irradiance influence on climate. |
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