Connecting regional aerosol emissions reductions to local and remote precipitation responses

<p>The unintended climatic implications of aerosol and precursor emission reductions implemented to protect public health are poorly understood. We investigate the precipitation response to regional changes in aerosol emissions using three coupled chemistry–climate models: NOAA Geophysical...

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Main Authors: D. M. Westervelt, A. J. Conley, A. M. Fiore, J.-F. Lamarque, D. T. Shindell, M. Previdi, N. R. Mascioli, G. Faluvegi, G. Correa, L. W. Horowitz
Format: Article
Language:English
Published: Copernicus Publications 2018-08-01
Series:Atmospheric Chemistry and Physics
Online Access:https://www.atmos-chem-phys.net/18/12461/2018/acp-18-12461-2018.pdf
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author D. M. Westervelt
D. M. Westervelt
A. J. Conley
A. M. Fiore
A. M. Fiore
J.-F. Lamarque
D. T. Shindell
M. Previdi
N. R. Mascioli
N. R. Mascioli
G. Faluvegi
G. Faluvegi
G. Correa
L. W. Horowitz
author_facet D. M. Westervelt
D. M. Westervelt
A. J. Conley
A. M. Fiore
A. M. Fiore
J.-F. Lamarque
D. T. Shindell
M. Previdi
N. R. Mascioli
N. R. Mascioli
G. Faluvegi
G. Faluvegi
G. Correa
L. W. Horowitz
author_sort D. M. Westervelt
collection DOAJ
description <p>The unintended climatic implications of aerosol and precursor emission reductions implemented to protect public health are poorly understood. We investigate the precipitation response to regional changes in aerosol emissions using three coupled chemistry–climate models: NOAA Geophysical Fluid Dynamics Laboratory Coupled Model 3 (GFDL-CM3), NCAR Community Earth System Model (CESM1), and NASA Goddard Institute for Space Studies ModelE2 (GISS-E2). Our approach contrasts a long present-day control simulation from each model (up to 400 years with perpetual year 2000 or 2005 emissions) with 14 individual aerosol emissions perturbation simulations (160–240 years each). We perturb emissions of sulfur dioxide and/or carbonaceous aerosol within six world regions and assess the significance of precipitation responses relative to internal variability determined by the control simulation and across the models. Global and regional precipitation mostly increases when we reduce regional aerosol emissions in the models, with the strongest responses occurring for sulfur dioxide emissions reductions from Europe and the United States. Precipitation responses to aerosol emissions reductions are largest in the tropics and project onto the El Niño–Southern Oscillation (ENSO). Regressing precipitation onto an Indo-Pacific zonal sea level pressure gradient index (a proxy for ENSO) indicates that the ENSO component of the precipitation response to regional aerosol removal can be as large as 20&thinsp;% of the total simulated response. Precipitation increases in the Sahel in response to aerosol reductions in remote regions because an anomalous interhemispheric temperature gradient alters the position of the Intertropical Convergence Zone (ITCZ). This mechanism holds across multiple aerosol reduction simulations and models.</p>
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spelling doaj.art-76c39054c7a34f0c88391b3db4a1f0622022-12-22T01:34:37ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242018-08-0118124611247510.5194/acp-18-12461-2018Connecting regional aerosol emissions reductions to local and remote precipitation responsesD. M. Westervelt0D. M. Westervelt1A. J. Conley2A. M. Fiore3A. M. Fiore4J.-F. Lamarque5D. T. Shindell6M. Previdi7N. R. Mascioli8N. R. Mascioli9G. Faluvegi10G. Faluvegi11G. Correa12L. W. Horowitz13Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, USANASA Goddard Institute for Space Studies, New York, New York, USANational Center for Atmospheric Research, Boulder, Colorado, USALamont-Doherty Earth Observatory, Columbia University, Palisades, New York, USADepartment of Earth and Environmental Sciences, Columbia University, Palisades, New York, USANational Center for Atmospheric Research, Boulder, Colorado, USANicholas School of the Environment, Duke University. Durham, North Carolina, USALamont-Doherty Earth Observatory, Columbia University, Palisades, New York, USALamont-Doherty Earth Observatory, Columbia University, Palisades, New York, USADepartment of Earth and Environmental Sciences, Columbia University, Palisades, New York, USANASA Goddard Institute for Space Studies, New York, New York, USACenter for Climate Systems Research, Columbia University, New York, New York, USALamont-Doherty Earth Observatory, Columbia University, Palisades, New York, USANational Oceanic and Atmospheric Administration, Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey, USA<p>The unintended climatic implications of aerosol and precursor emission reductions implemented to protect public health are poorly understood. We investigate the precipitation response to regional changes in aerosol emissions using three coupled chemistry–climate models: NOAA Geophysical Fluid Dynamics Laboratory Coupled Model 3 (GFDL-CM3), NCAR Community Earth System Model (CESM1), and NASA Goddard Institute for Space Studies ModelE2 (GISS-E2). Our approach contrasts a long present-day control simulation from each model (up to 400 years with perpetual year 2000 or 2005 emissions) with 14 individual aerosol emissions perturbation simulations (160–240 years each). We perturb emissions of sulfur dioxide and/or carbonaceous aerosol within six world regions and assess the significance of precipitation responses relative to internal variability determined by the control simulation and across the models. Global and regional precipitation mostly increases when we reduce regional aerosol emissions in the models, with the strongest responses occurring for sulfur dioxide emissions reductions from Europe and the United States. Precipitation responses to aerosol emissions reductions are largest in the tropics and project onto the El Niño–Southern Oscillation (ENSO). Regressing precipitation onto an Indo-Pacific zonal sea level pressure gradient index (a proxy for ENSO) indicates that the ENSO component of the precipitation response to regional aerosol removal can be as large as 20&thinsp;% of the total simulated response. Precipitation increases in the Sahel in response to aerosol reductions in remote regions because an anomalous interhemispheric temperature gradient alters the position of the Intertropical Convergence Zone (ITCZ). This mechanism holds across multiple aerosol reduction simulations and models.</p>https://www.atmos-chem-phys.net/18/12461/2018/acp-18-12461-2018.pdf
spellingShingle D. M. Westervelt
D. M. Westervelt
A. J. Conley
A. M. Fiore
A. M. Fiore
J.-F. Lamarque
D. T. Shindell
M. Previdi
N. R. Mascioli
N. R. Mascioli
G. Faluvegi
G. Faluvegi
G. Correa
L. W. Horowitz
Connecting regional aerosol emissions reductions to local and remote precipitation responses
Atmospheric Chemistry and Physics
title Connecting regional aerosol emissions reductions to local and remote precipitation responses
title_full Connecting regional aerosol emissions reductions to local and remote precipitation responses
title_fullStr Connecting regional aerosol emissions reductions to local and remote precipitation responses
title_full_unstemmed Connecting regional aerosol emissions reductions to local and remote precipitation responses
title_short Connecting regional aerosol emissions reductions to local and remote precipitation responses
title_sort connecting regional aerosol emissions reductions to local and remote precipitation responses
url https://www.atmos-chem-phys.net/18/12461/2018/acp-18-12461-2018.pdf
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