Publication Abstracts

Westervelt et al. 2017

Westervelt, D.M., A.J. Conley, A.M. Fiore, J.-F. Lamarque, D. Shindell, M. Previdi, G. Faluvegi, G. Correa, and L.W. Horowitz, 2017: Multimodel precipitation responses to removal of U.S. sulfur dioxide emissions. J. Geophys. Res. Atmos., 122, no. 9, 5024-5038, doi:10.1002/2017JD026756.

Emissions of aerosols and their precursors are declining due to policies enacted to protect human health, yet we currently lack a full understanding of the magnitude, spatiotemporal pattern, statistical significance, and physical mechanisms of precipitation responses to aerosol reductions. We quantify the global and regional precipitation response to U.S. SO2 emissions reductions using three fully coupled chemistry-climate models: Community Earth System Model version 1, Geophysical Fluid Dynamics Laboratory Coupled Model 3, and Goddard Institute for Space Studies ModelE2. We contrast 200 year (or longer) simulations in which anthropogenic U.S. sulfur dioxide (SO2) emissions are set to zero with present-day control simulations to assess the aerosol, cloud, and precipitation response to U.S. SO2 reductions. In all three models, reductions in aerosol optical depth up to 70% and cloud droplet number column concentration up to 60% occur over the eastern U.S. and extend over the Atlantic Ocean. Precipitation responses occur both locally and remotely, with the models consistently showing an increase in most regions considered. We find a northward shift of the tropical rain belt location of up to 0.35° latitude especially near the Sahel, where the rainy season length and intensity are significantly enhanced in two of the three models. This enhancement is the result of greater warming in the Northern versus Southern Hemisphere, which acts to shift the Intertropical Convergence Zone (ITCZ) northward, delivering additional wet season rainfall to the Sahel. Two of our three models thus imply a previously unconsidered benefit of continued U.S. SO2 reductions for Sahel precipitation.

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BibTeX Citation

  author={Westervelt, D. M. and Conley, A. J. and Fiore, A. M. and Lamarque, J.-F. and Shindell, D. and Previdi, M. and Faluvegi, G. and Correa, G. and Horowitz, L. W.},
  title={Multimodel precipitation responses to removal of U.S. sulfur dioxide emissions},
  journal={Journal of Geophysical Research: Atmospheres},

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RIS Citation

ID  - we05100p
AU  - Westervelt, D. M.
AU  - Conley, A. J.
AU  - Fiore, A. M.
AU  - Lamarque, J.-F.
AU  - Shindell, D.
AU  - Previdi, M.
AU  - Faluvegi, G.
AU  - Correa, G.
AU  - Horowitz, L. W.
PY  - 2017
TI  - Multimodel precipitation responses to removal of U.S. sulfur dioxide emissions
JA  - J. Geophys. Res. Atmos.
JO  - Journal of Geophysical Research: Atmospheres
VL  - 122
IS  - 9
SP  - 5024
EP  - 5038
DO  - 10.1002/2017JD026756
ER  -

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