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| Titel |
Development and basic evaluation of a prognostic aerosol scheme (v1) in the CNRM Climate Model CNRM-CM6 |
| VerfasserIn |
M. Michou, P. Nabat, D. Saint-Martin |
| 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 ; 8, no. 3 ; Nr. 8, no. 3 (2015-03-09), S.501-531 |
| Datensatznummer |
250116174
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| Publikation (Nr.) |
 copernicus.org/gmd-8-501-2015.pdf |
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| Zusammenfassung |
| We have implemented a prognostic aerosol scheme (v1) in CNRM-CM6, the climate
model of CNRM-GAME and CERFACS, based upon the GEMS/MACC aerosol module of
the ECMWF operational forecast model. This scheme describes the physical
evolution of the five main types of aerosols, namely black carbon, organic
matter, sulfate, desert dust and sea salt. In this work, we describe the
characteristics of our implementation, for instance, taking into
consideration a different dust scheme or boosting biomass burning emissions
by a factor of 2, as well as the evaluation performed on simulation output.
The simulations consist of time slice simulations for 2004 conditions and
transient runs over the 1993–2012 period, and are either free-running or
nudged towards the ERA-Interim Reanalysis. Evaluation data sets include
several satellite instrument AOD (aerosol optical depth) products (i.e., MODIS Aqua classic and
Deep-Blue products, MISR and CALIOP products), as well as ground-based
AERONET data and the derived AERONET climatology, MAC-v1. The uncertainty of
aerosol-type seasonal AOD due to model internal variability is low over large
parts of the globe, and the characteristics of a nudged simulation reflect
those of a free-running simulation. In contrast, the impact of the new dust
scheme is large, with modelled dust AODs from simulations with the new dust
scheme close to observations. Overall patterns and seasonal cycles of the
total AOD are well depicted with, however, a systematic low bias over oceans.
The comparison to the fractional MAC-v1 AOD climatology shows disagreements
mostly over continents, while that to AERONET sites outlines the capability
of the model to reproduce monthly climatologies under very diverse dominant
aerosol types. Here again, underestimation of the total AOD appears in
several cases, sometimes linked to insufficient efficiency of the aerosol
transport away from the aerosol sources. Analysis of monthly time series at
166 AERONET sites shows, in general, correlation coefficients higher than 0.5
and lower model variance than observed. A large interannual variability can
also be seen in the CALIOP vertical profiles over certain regions of the
world. Overall, this prognostic aerosol scheme appears promising for
aerosol-climate studies. There is room, however, for implementing more
complex parameterisations in relation to aerosols. |
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