 |
| Titel |
Soot microphysical effects on liquid clouds, a multi-model investigation |
| VerfasserIn |
D. Koch, Y. Balkanski, S. E. Bauer, R. C. Easter, S. Ferrachat, S. J. Ghan, C. Hoose, T. Iversen, A. Kirkevåg, J. E. Kristjánsson, X. Liu, U. Lohmann, S. Menon, J. Quaas, M. Schulz, Ø. Seland, T. Takemura, N. Yan |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 3 ; Nr. 11, no. 3 (2011-02-07), S.1051-1064 |
| Datensatznummer |
250009291
|
| Publikation (Nr.) |
 copernicus.org/acp-11-1051-2011.pdf |
|
|
|
|
|
| Zusammenfassung |
| We use global models to explore the microphysical effects of carbonaceous
aerosols on liquid clouds. Although absorption of solar radiation by soot
warms the atmosphere, soot may cause climate cooling due to its contribution
to cloud condensation nuclei (CCN) and therefore cloud brightness. Six
global models conducted three soot experiments; four of the models had
detailed aerosol microphysical schemes. The average cloud radiative response
to biofuel soot (black and organic carbon), including both indirect and
semi-direct effects, is −0.11 Wm−2, comparable in size but opposite in
sign to the respective direct effect. In a more idealized fossil fuel black
carbon experiment, some models calculated a positive cloud response because
soot provides a deposition sink for sulfuric and nitric acids and secondary
organics, decreasing nucleation and evolution of viable CCN. Biofuel soot
particles were also typically assumed to be larger and more hygroscopic than
for fossil fuel soot and therefore caused more negative forcing, as also
found in previous studies. Diesel soot (black and organic carbon)
experiments had relatively smaller cloud impacts with five of the models <±0.06 Wm−2
from clouds. The results are subject to the caveats
that variability among models, and regional and interrannual variability for
each model, are large. This comparison together with previously published
results stresses the need to further constrain aerosol microphysical
schemes. The non-linearities resulting from the competition of opposing
effects on the CCN population make it difficult to extrapolate from
idealized experiments to likely impacts of realistic potential emission
changes. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|