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| Titel |
Interactive ozone and methane chemistry in GISS-E2 historical and future climate simulations |
| VerfasserIn |
D. T. Shindell  , O. Pechony, A. Voulgarakis, G. Faluvegi, L. Nazarenko, J.-F. Lamarque, K. Bowman, G. Milly, B. Kovari, R. Ruedy, G. A. Schmidt |
| 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. 5 ; Nr. 13, no. 5 (2013-03-05), S.2653-2689 |
| Datensatznummer |
250018476
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| Publikation (Nr.) |
 copernicus.org/acp-13-2653-2013.pdf |
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| Zusammenfassung |
| The new generation GISS climate model includes fully interactive chemistry
related to ozone in historical and future simulations, and interactive
methane in future simulations. Evaluation of ozone, its tropospheric
precursors, and methane shows that the model captures much of the
large-scale spatial structure seen in recent observations. While the model
is much improved compared with the previous chemistry-climate model,
especially for ozone seasonality in the stratosphere, there is still
slightly too rapid stratospheric circulation, too little
stratosphere-to-troposphere ozone flux in the Southern Hemisphere and an
Antarctic ozone hole that is too large and persists too long. Quantitative
metrics of spatial and temporal correlations with satellite datasets as well
as spatial autocorrelation to examine transport and mixing are presented to
document improvements in model skill and provide a benchmark for future
evaluations. The difference in radiative forcing (RF) calculated using
modeled tropospheric ozone versus tropospheric ozone observed by TES is only
0.016 W m−2. Historical 20th Century simulations show a steady
increase in whole atmosphere ozone RF through 1970 after which there is a
decrease through 2000 due to stratospheric ozone depletion. Ozone forcing
increases throughout the 21st century under RCP8.5 owing to a projected
recovery of stratospheric ozone depletion and increases in methane, but
decreases under RCP4.5 and 2.6 due to reductions in emissions of other ozone
precursors. RF from methane is 0.05 to 0.18 W m−2 higher in our model
calculations than in the RCP RF estimates. The surface temperature response
to ozone through 1970 follows the increase in forcing due to tropospheric
ozone. After that time, surface temperatures decrease as ozone RF declines
due to stratospheric depletion. The stratospheric ozone depletion also
induces substantial changes in surface winds and the Southern Ocean
circulation, which may play a role in a slightly stronger response per unit
forcing during later decades. Tropical precipitation shifts south during
boreal summer from 1850 to 1970, but then shifts northward from 1970 to
2000, following upper tropospheric temperature gradients more strongly than
those at the surface. |
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