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| Titel |
The role of sea ice in slowly rotating aquaplanet simulations |
| VerfasserIn |
Josiane Salameh, Max Popp, Jochem Marotzke |
| 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 |
250135514
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| Publikation (Nr.) |
 EGU/EGU2016-16390.pdf |
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| Zusammenfassung |
| A large fraction of recently discovered exoplanets are found in close orbit from their star.
Their rotation period is expected to be slow due to important tidal forces. Therefore, in order
to assess the habitability of slowly rotating planets, it is imperative to understand how slow
rotation periods affect the climate. Under different Earth-like configurations, previous studies
focused on the special case of synchronous rotation where the orbital and planetary rotation
periods are identical. In addition, simulations with non-synchronous rotations did not account
for sea ice. Therefore, we turn on the thermodynamics sea-ice model in the state-of-the-art
atmospheric general circulation model ECHAM6 coupled to a mixed-layer ocean and
investigate the aquaplanet’s climate across rotation periods between one and 365 Earth days.
Simulations with the sea-ice model turned on show a global-mean surface temperature
up to 25 K lower than simulations with the sea-ice model turned off, particularly
for rotation periods between 64 and 300 days. For both type of experiments, the
climate cools with increasing rotation period. However, when sea ice is included, the
significant drop in the global-mean surface temperature is due to sea-ice reaching low
latitudes. Then, beyond a 200 days rotation period, sea ice grows over the equatorial
region during the nighttime and persists well into the daytime. This causes a high
contribution of the sea-ice albedo to the planetary albedo. Our study illustrates, thus,
that sea-ice plays a crucial role in shaping the climate on slowly rotating planets. |
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