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| Titel |
Climatic effects of 1950-2050 changes in US anthropogenic aerosols – Part 2: Climate response |
| VerfasserIn |
E. M. Leibensperger, L. J. Mickley, D. J. Jacob, W.-T. Chen, J. H. Seinfeld, A. Nenes, P. J. Adams, D. G. Streets, N. Kumar, D. Rind |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 12, no. 7 ; Nr. 12, no. 7 (2012-04-10), S.3349-3362 |
| Datensatznummer |
250011016
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| Publikation (Nr.) |
 copernicus.org/acp-12-3349-2012.pdf |
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| Zusammenfassung |
| We investigate the climate response to changing US anthropogenic aerosol
sources over the 1950–2050 period by using the NASA GISS general circulation
model (GCM) and comparing to observed US temperature trends. Time-dependent
aerosol distributions are generated from the GEOS-Chem chemical transport
model applied to historical emission inventories and future projections.
Radiative forcing from US anthropogenic aerosols peaked in 1970–1990 and has
strongly declined since due to air quality regulations. We find that the
regional radiative forcing from US anthropogenic aerosols elicits a strong
regional climate response, cooling the central and eastern US by 0.5–1.0 °C
on average during 1970–1990, with the strongest effects on maximum
daytime temperatures in summer and autumn. Aerosol cooling reflects
comparable contributions from direct and indirect (cloud-mediated) radiative
effects. Absorbing aerosol (mainly black carbon) has negligible warming
effect. Aerosol cooling reduces surface evaporation and thus decreases
precipitation along the US east coast, but also increases the southerly flow
of moisture from the Gulf of Mexico resulting in increased cloud cover and
precipitation in the central US. Observations over the eastern US show a
lack of warming in 1960–1980 followed by very rapid warming since, which we
reproduce in the GCM and attribute to trends in US anthropogenic aerosol
sources. Present US aerosol concentrations are sufficiently low that future
air quality improvements are projected to cause little further warming in
the US (0.1 °C over 2010–2050). We find that most of the warming from
aerosol source controls in the US has already been realized over the
1980–2010 period. |
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