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| Titel |
The relationship between aerosol model uncertainty and radiative forcing uncertainty |
| VerfasserIn |
Ken Carslaw, Lindsay Lee, Carly Reddington |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250133010
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| Publikation (Nr.) |
 EGU/EGU2016-13574.pdf |
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| Zusammenfassung |
| There has been no systematic assessment of how reduction in the uncertainty of global aerosol models will feed through to the uncertainty in the predicted forcing. We use a global model perturbed parameter ensemble to show that tight observational constraint of aerosol concentrations in the model has a relatively small effect on the aerosol-related uncertainty in the calculated aerosol-cloud forcing between pre-industrial and present day periods. One factor is the low sensitivity of present-day aerosol to natural emissions that determine the pre-industrial aerosol state. But the major cause of the weak constraint is that the full uncertainty space of the model generates a large number of model variants that are “equally acceptable” compared to present-day aerosol observations. The narrow range of aerosol concentrations in the observationally constrained model gives the impression of low aerosol model uncertainty, but this hides a range of very different aerosol models. These multiple so-called “equifinal” model variants predict a wide range of forcings. Equifinality in the aerosol model means that tuning of a small number of model processes to achieve model-observation agreement could give a misleading impression of model robustness. |
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