 |
| Titel |
Energy balance and meridional energy transport in PCMDI/CMIP3 GCMs |
| VerfasserIn |
V. Lucarini, F. Ragone |
| Konferenz |
EGU General Assembly 2009
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250020678
|
|
|
|
|
|
| Zusammenfassung |
| We perform a thorough analysis of the energy balance at the top of the atmosphere (TOA) and
at surface (SUR) of the GCMs included in the PCMDI/CMIP3 dataset. We consider
preindustrial controls runs and SRESA1B future climate scenario runs. Most models feature
serious positive imbalances (up to over 3W∕m2) when the TOA budget is considered, which
implies that a spurious, offsetting cooling must be present in order to determine the observed
driftless climate. None of the atmospheric, land and ocean components are balanced. In
each SRESA1B run, global warming corresponds to positive TOA budget which
peaks during the 100 years of increasing concentration of CO2. When the CO2
concentration is stabilized at 720 ppm, the positive balance decays exponentially
with a tau of about 500 years, which corresponds to the slowest - oceanic - time
scale. The TOA radiative offset of the newly adjusted climate is different from that
of the preindustrial control run. This flaw may partially explain why the GCMs’
span of temperature increases due to CO2 concentration change is so large. When
considering meridional energy transports, we observe that in both hemispheres the
location and value of the peak of the atmospheric and oceanic transport greatly differ
among models, whereas the models’ agreement for the total transport is better. This
suggests that some compensation may be in place. In increased CO2 concentration
conditions, the total meridional transport increases, resulting from a relevant increase
of the atmospheric component and a slight decrease of the oceanic component.
Instead, the position of the peaks of the meridional transport is basically unchanged. |
|
|
|
|
|
|