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| Titel |
The impact of emission and climate change on ozone in the United States under representative concentration pathways (RCPs) |
| VerfasserIn |
Y. Gao, J. S. Fu, J. B. Drake, J.-F. Lamarque, Y. Liu |
| 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 ; 13, no. 18 ; Nr. 13, no. 18 (2013-09-27), S.9607-9621 |
| Datensatznummer |
250085721
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| Publikation (Nr.) |
 copernicus.org/acp-13-9607-2013.pdf |
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| Zusammenfassung |
Dynamical downscaling was applied in this study to link the global
climate-chemistry model Community Atmosphere Model (CAM-Chem) with the
regional models Weather Research and Forecasting (WRF) Model and Community
Multi-scale Air Quality (CMAQ). Two representative concentration pathway
(RCP) scenarios (RCP 4.5 and RCP 8.5) were used to evaluate the climate
impact on ozone concentrations in the 2050s.
From the CAM-Chem global simulation results, ozone concentrations in the
lower to mid-troposphere (surface to ~300 hPa), from mid- to
high latitudes in the Northern Hemisphere, decreases by the end of the 2050s
(2057–2059) in RCP 4.5 compared to present (2001–2004), with the largest
decrease of 4–10 ppbv occurring in the summer and the fall; and an increase as
high as 10 ppbv in RCP 8.5 resulting from the increased methane emissions.
From the regional model CMAQ simulation results, under the RCP 4.5 scenario
(2057–2059), in the summer when photochemical reactions are the most active,
the large ozone precursor emissions reduction leads to the greatest decrease
of downscaled surface ozone concentrations compared to present (2001–2004),
ranging from 6 to 10 ppbv. However, a few major cities show ozone increases
of 3 to 7 ppbv due to weakened NO titration. Under the RCP 8.5 scenario, in
winter, downscaled ozone concentrations increase across nearly the entire
continental US in winter, ranging from 3 to 10 ppbv due to increased methane
emissions. More intense heat waves are projected to occur by the end of
the 2050s in RCP 8.5, leading to a 0.3 ppbv to 2.0 ppbv increase (statistically
significant except in the Southeast) of the mean maximum daily 8 h daily average
(MDA8) ozone in nine climate regions in the US. Moreover, the upper
95% limit of MDA8 increase reaches 0.4 ppbv to 1.5 ppbv in RCP 4.5 and
0.6 ppbv to 3.2 ppbv in RCP 8.5. The magnitude differences of increase
between RCP 4.5 and 8.5 also reflect that the increase of methane emissions may
favor or strengthen the effect of heat waves. |
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