Publication Abstracts

Menon and Del Genio 2007

Menon, S., and A.D. Del Genio, 2007: Evaluating the impacts of carbonaceous aerosols on clouds and climate. In Human-Induced Climate Change: An Interdisciplinary Assessment. M.E. Schlesinger, H. Kheshgi, J.B. Smith, F.C. de la Chesnaye, J.M. Reilly, T. Wilson, and C. Kolstad, Eds. Cambridge University Press, pp. 34-48.

Aerosol effects on climate through the direct, semi-direct, thermodynamical, indirect effects and associated feedbacks can range from +0.8 to -2.4 W m-2, with an implied value of -1.0 W m-2 (range from -0.5 to -4.5 W m-2) for the aerosol indirect effects. These estimates are large compared to other forcings such as greenhouse gases, land-use, solar activity, and volcanic aerosol effects, that add up to ∼3.35 W m-2. However, the uncertainties associated with aerosol-cloud effects can also be quite large. In this paper, we focus on the role that carbonaceous aerosols play in climate change and evaluate the range in aerosol indirect effect estimates. Carbonaceous aerosols from biomass, fossil- and biofuel sources have different physical/optical properties and affect cloud properties differently for similar aerosol loadings. Regional changes in climate diagnostics are evaluated for these aerosol effects on warm stratiform and convective clouds with the Goddard Institute for Space Studies (GISS) climate model coupled to an on-line aerosol chemistry model. Ratio of changes of surface temperature to top of the atmosphere (TOA) radiative fluxes for twice the amount of fossil- and biofuel black carbon (BC) emissions with all indirect effects included is higher by over a factor of 10 (changes from 0.097 to 1.14 K W-1 m2). Although BC aerosols have smaller atmospheric burdens (∼0.13 mg m-2) compared to the other aerosols, its relatively stronger forcing efficiency suggests that they have a significant influence on climate. Including aerosol-convective cloud effects substantially lowers the indirect effect estimates (since longwave effects are comparable to shortwave effects), and level of precipitation initiation is shifter to higher atmospheric levels. Precipitation appeared to decrease significantly in the Amazonia when accounting for increased cloud droplets in biomass burning regions. Regional precipitation changes over China and India were found to correspond to the amount of atmospheric heating, with stronger radiative fluxes (heating) in the atmospheric column corresponding to larger changes (positive) in precipitation.

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BibTeX Citation

  author={Menon, S. and Del Genio, A. D.},
  editor={Schlesinger, M. E. and Kheshgi, H. and Smith, J. B. and de la Chesnaye, F. C. and Reilly, J. M. and Wilson, T. and Kolstad, C.},
  title={Evaluating the impacts of carbonaceous aerosols on clouds and climate},
  booktitle={Human-Induced Climate Change: An Interdisciplinary Assessment},
  publisher={Cambridge University Press},
  address={Cambridge, U.K.},

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RIS Citation

ID  - me01100t
AU  - Menon, S.
AU  - Del Genio, A. D.
ED  - Schlesinger, M. E.
ED  - Kheshgi, H.
ED  - Smith, J. B.
ED  - de la Chesnaye, F. C.
ED  - Reilly, J. M.
ED  - Wilson, T.
ED  - Kolstad, C.
PY  - 2007
TI  - Evaluating the impacts of carbonaceous aerosols on clouds and climate
BT  - Human-Induced Climate Change: An Interdisciplinary Assessment
SP  - 34
EP  - 48
PB  - Cambridge University Press
CY  - Cambridge, U.K.
ER  -

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