 |
| Titel |
Rate of non-linearity in DMS aerosol-cloud-climate interactions |
| VerfasserIn |
M. A. Thomas, P. Suntharalingam, L. Pozzoli, A. Devasthale, S. Kloster, S. Rast, J. Feichter, T. M. Lenton |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 21 ; Nr. 11, no. 21 (2011-11-10), S.11175-11183 |
| Datensatznummer |
250010181
|
| Publikation (Nr.) |
 copernicus.org/acp-11-11175-2011.pdf |
|
|
|
|
|
| Zusammenfassung |
| The degree of non-linearity in DMS-cloud-climate interactions is assessed
using the ECHAM5-HAMMOZ model by taking into account end-to-end aerosol
chemistry-cloud microphysics link. The evaluation is made over the Southern
oceans in austral summer, a region of minimal anthropogenic influence. In
this study, we compare the DMS-derived changes in the aerosol and cloud
microphysical properties between a baseline simulation with the ocean DMS
emissions from a prescribed climatology, and a scenario where the DMS
emissions are doubled. Our results show that doubling the DMS emissions in
the current climate results in a non-linear response in atmospheric DMS
burden and subsequently, in SO2 and H2SO4 burdens due to
inadequate OH oxidation. The aerosol optical depth increases by only
~20 % in the 30° S–75° S belt in the SH summer
months. This increases the vertically integrated cloud droplet number
concentrations (CDNC) by 25 %. Since the vertically integrated liquid
water vapor is constant in our model simulations, an increase in CDNC leads
to a reduction in cloud droplet radius of 3.4 % over the Southern oceans
in summer. The equivalent increase in cloud liquid water path is 10.7 %.
The above changes in cloud microphysical properties result in a change in
global annual mean radiative forcing at the TOA of −1.4 W m−2. The
results suggest that the DMS-cloud microphysics link is highly non-linear.
This has implications for future studies investigating the DMS-cloud climate
feedbacks in a warming world and for studies evaluating geoengineering
options to counteract warming by modulating low level marine clouds. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|