Publication Abstracts

Bauer and Menon 2012

Bauer, S.E., and S. Menon, 2012: Aerosol direct, indirect, semi-direct and surface albedo effects from sector contributions based on the IPCC AR5 emissions for pre-industrial and present day conditions. J. Geophys. Res., 117, no. D1, D01206, doi:10.1029/2011JD016816.

The anthropogenic increase in aerosol concentrations since pre-industrial times and its net cooling effect on the atmosphere is thought to mask some of the greenhouse gas induced warming. Although the overall effect of aerosols on solar radiation and clouds is most certainly negative, some individual forcing agents and feedbacks have positive forcing effects. Recent studies have tried to identify some of those positive forcing agents and their individual emission sectors, with the hope that mitigation policies could be developed to target those emitters. Understanding the net effect of multi source emitting sectors and the involved cloud feedbacks is very challenging and this paper will clarify forcing and feedback effects by separating direct, indirect, semi-direct and surface albedo effects due to aerosols. To this end, we apply the GISS climate model including detailed aerosol microphysics to examine aerosol impacts on climate by isolating single emission sector contributions as given by the CMIP5 emission datasets developed for IPCC AR5. For the past 150 years modeled, using the climate model and emissions from pre-industrial times to present-day, the total global annual mean aerosol radiative forcing is -0.6 W/m2, with the largest contribution from the direct effect (-0.5 W/m2). Aerosol induced changes on cloud cover often depends on cloud type and geographical region. The indirect (-0.17 W/m2) and semi-direct effects (-0.10 W/m2) can be isolated on a regional scale, and often have opposing forcing effects, leading to overall small forcing effects on a global scale. Although the surface albedo effects from aerosols are small (0.016 W/m2), triggered feedbacks on TOA radiaitve forcing can be ten times larger. Our results point out that each emission sector has varying impacts by geographical region. For example the single sector most responsible for a net positive radiative forcing is the transportation sector in the United States, agricultural burning and transportation in Europe, and the domestic emission sector in Asia. These sectors are attractive mitigation targets.

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BibTeX Citation

@article{ba00400a,
  author={Bauer, S. E. and Menon, S.},
  title={Aerosol direct, indirect, semi-direct and surface albedo effects from sector contributions based on the IPCC AR5 emissions for pre-industrial and present day conditions},
  year={2012},
  journal={Journal of Geophysical Research},
  volume={117},
  number={D1},
  pages={D01206},
  doi={10.1029/2011JD016816},
}

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RIS Citation

TY  - JOUR
ID  - ba00400a
AU  - Bauer, S. E.
AU  - Menon, S.
PY  - 2012
TI  - Aerosol direct, indirect, semi-direct and surface albedo effects from sector contributions based on the IPCC AR5 emissions for pre-industrial and present day conditions
JA  - J. Geophys. Res.
JO  - Journal of Geophysical Research
VL  - 117
IS  - D1
SP  - D01206
DO  - 10.1029/2011JD016816
ER  -

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