Non-linearity in DMS aerosol-cloud-climate interactions

Thomas, MA, Suntharalingam, P, Pozzoli, L, Devasthale, A, Kloster, S, Rast, S, Feichter, J and Lenton, TM (2011) Non-linearity in DMS aerosol-cloud-climate interactions. Atmospheric Chemistry and Physics, 11 (5). pp. 15227-15253. ISSN 1680-7324

Full text not available from this repository. (Request a copy)

Abstract

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 SO 2 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 radiatve 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.

Item Type: Article
Faculty \ School: Faculty of Science > School of Environmental Sciences
Depositing User: Rosie Cullington
Date Deposited: 06 Jun 2011 13:55
Last Modified: 21 Apr 2020 16:54
URI: https://ueaeprints.uea.ac.uk/id/eprint/31849
DOI: 10.5194/acp-11-11175-2011

Actions (login required)

View Item View Item