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| Titel |
Albedo and heat transport in 3-D model simulations of the early Archean climate |
| VerfasserIn |
H. Kienert, G. Feulner, V. Petoukhov |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 9, no. 4 ; Nr. 9, no. 4 (2013-08-07), S.1841-1862 |
| Datensatznummer |
250085201
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| Publikation (Nr.) |
 copernicus.org/cp-9-1841-2013.pdf |
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| Zusammenfassung |
| At the beginning of the Archean eon (ca. 3.8 billion years ago), the Earth's
climate state was significantly different from today due to the lower solar
luminosity, smaller continental fraction, higher rotation rate and,
presumably, significantly larger greenhouse gas concentrations. All these
aspects play a role in solutions to the "faint young Sun paradox" which
must explain why the ocean surface was not fully frozen at that time. Here,
we present 3-D model simulations of climate states that are consistent with
early Archean boundary conditions and have different CO2 concentrations,
aiming at an understanding of the fundamental characteristics of the early
Archean climate system. In order to do so, we have appropriately modified an
intermediate complexity climate model that couples a statistical-dynamical
atmosphere model (involving parameterizations of the dynamics) to an ocean
general circulation model and a thermodynamic-dynamic sea-ice model. We focus
on three states: one of them is ice-free, one has the same mean surface air
temperature of 288 K as today's Earth and the third one is the coldest
stable state in which there is still an area with liquid surface water
(i.e. the critical state at the transition to a "snowball Earth"). We find
a reduction in meridional heat transport compared to today, which leads to a
steeper latitudinal temperature profile and has atmospheric as well as
oceanic contributions. Ocean surface velocities are largely zonal, and the
strength of the atmospheric meridional circulation is significantly reduced
in all three states. These aspects contribute to the observed relation
between global mean temperature and albedo, which we suggest as a
parameterization of the ice-albedo feedback for 1-D model simulations of the
early Archean and thus the faint young Sun problem. |
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