 |
| Titel |
Microphysical, macrophysical and radiative signatures of volcanic aerosols in trade wind cumulus observed by the A-Train |
| VerfasserIn |
T. Yuan, L. A. Remer, H. Yu |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 14 ; Nr. 11, no. 14 (2011-07-21), S.7119-7132 |
| Datensatznummer |
250009935
|
| Publikation (Nr.) |
 copernicus.org/acp-11-7119-2011.pdf |
|
|
|
|
|
| Zusammenfassung |
| Increased aerosol concentrations can raise planetary albedo not only by
reflecting sunlight and increasing cloud albedo, but also by changing cloud
amount. However, detecting aerosol effect on cloud amount has been elusive
to both observations and modeling due to potential buffering mechanisms and
convolution of meteorology. Here through a natural experiment provided by
long-term degassing of a low-lying volcano and use of A-Train satellite
observations, we show modifications of trade cumulus cloud fields including
decreased droplet size, decreased precipitation efficiency and increased
cloud amount are associated with volcanic aerosols. In addition we find
significantly higher cloud tops for polluted clouds. We demonstrate that the
observed microphysical and macrophysical changes cannot be explained by
synoptic meteorology or the orographic effect of the Hawaiian Islands. The
"total shortwave aerosol forcin", resulting from direct and indirect
forcings including both cloud albedo and cloud amount, is almost an order of
magnitude higher than aerosol direct forcing alone. Furthermore, the
precipitation reduction associated with enhanced aerosol leads to large
changes in the energetics of air-sea exchange and trade wind boundary layer.
Our results represent the first observational evidence of large-scale
increase of cloud amount due to aerosols in a trade cumulus regime, which
can be used to constrain the representation of aerosol-cloud interactions in
climate models. The findings also have implications for volcano-climate
interactions and climate mitigation research. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|