Open AccessIndirect sulphate aerosol forcing in a climate model with an interactive sulphur cycle
Author(s) -
Jones Andy,
Roberts David L.,
Woodage Margaret J.,
Johnson Colin E.
Publication year - 2001
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2000jd000089
Subject(s) - aerosol , radiative forcing , forcing (mathematics) , cloud forcing , cloud albedo , environmental science , atmospheric sciences , albedo (alchemy) , precipitation , climatology , climate model , sea salt aerosol , climate change , sea salt , meteorology , cloud cover , cloud computing , physics , geology , art , oceanography , performance art , computer science , art history , operating system
The effects of anthropogenic sulphate aerosol on cloud albedo and on precipitation efficiency (the first and second indirect effects, respectively) are investigated using a new version of the Hadley Centre climate model. This version includes a new cloud microphysics scheme, an interactive sulphur cycle, and a parameterization of the effects of sea salt aerosol. The combined global mean radiative impact from both indirect effects is estimated to be approximately −1.9 W m −2 in terms of the change in net cloud forcing, with the “albedo” effect dominating: we obtain values of −1.3 and −0.5 W m −2 for the first and second effects, respectively, when calculated separately. The estimate for the combined effect has at least a factor of 2 uncertainty associated with it: for example, alternative assumptions which affect the concentration of natural “background” sulphate aerosol reduce the forcing by over 25%, and different parameterizations of the autoconversion of cloud droplets to rainwater can double the forcing.