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| Titel |
Partitioning the influence of regional warming and feedbacks in the global response to abrupt CO2 forcing |
| VerfasserIn |
Christopher Hedemann, Thorsten Mauritsen, Johann Jungclaus, Jochem Marotzke |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250148581
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| Publikation (Nr.) |
 EGU/EGU2017-12850.pdf |
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| Zusammenfassung |
| We present a new analytical framework for diagnosing the regional causes of
state-dependence in global radiative feedbacks. We apply this framework in long runs
(∼1000 years) with the coupled climate model MPI-ESM-LR 1.2, subject to abrupt
increases in CO2 concentration, including 2-, 4-, 8- and 16-times the pre-industrial
levels. Two existing theories link a changing global feedback parameter to regional
processes: either changing regional warming patterns activate constant regional
feedbacks – “the pattern effect” – or the regional feedbacks themselves change
–“regional state-dependence”. Previous studies have typically tested one theory
under particular conditions; we apply our method to diagnose both effects across
a range of timescales and forcing strengths. Preliminary results indicate that the
influence of the pattern effect is restricted to the initial warming phase. During the first
decades of warming, ocean heat uptake allows regional warming to be non-linear with
respect to the global mean, which our framework indicates is a necessary condition
for the pattern effect. The evolution of global feedbacks over the remainder of the
warming response is dominated by regional state-dependence and determined by
the forcing strength. By identifying the conditions necessary for these effects to
influence the global radiative response, we propose a link between both theories. |
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