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| Titel |
Assimilation of Earth Rotation Parameters into a global ocean model: Governing physical mechanisms |
| VerfasserIn |
Jan Saynisch, Manfred Wenzel, Jens Schröter |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250033743
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| Zusammenfassung |
| The presented study focuses on that Earth rotation anomalies that are
induced by the oceans. Changes in the oceanic current system and in
the oceanic mass distribution alter the state of the Earth's rotation
which is characterized by the length of day and the tilt of the
pole-to-pole axis. The aim of our study is to derive the respective
governing physical mechanisms. Therefore, Earth rotation observations
were assimilated with a global circulation model of the ocean.
Although assimilation is a well established tool in climate science
the assimilation of Earth rotation observations with a global ocean
model is done here for the first time. Prior to the assimilation,
Earth rotation observations had to be projected onto the angular
momentum of the ocean. Non-oceanic contributions had to be
removed. The result of the subsequent assimilation procedure is a time
varying ocean model state, i.e. a trajectory, that reproduces the
projected Earth rotation observations well. Afterwards, this
trajectory was studied to understand the generation of Earth rotation
deviations by the ocean. The governing physical mechanisms could be
identified: Changes in length of day correlate to changes in
global ocean mass. Changes in the ocean current system and in the
spatial distribution of ocean mass dominate the oceanic generation of
polar movement. |
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