Synonyms
Definition
Excitation of Polar Motion and Length of Day anomalies due to changes in ocean angular momentum.
Non-tidal Oceanic Excitation
Due to the conservation of angular momentum in the Earth system, changes in ocean angular momentum (OAM) excite corresponding changes in Earth’s rotation (Lambeck 1980). Since angular momentum is a function of mass distribution and angular velocity, OAM anomalies are traditionally divided into a mass and a motion term (see Fig. 1). The OAM mass term represents angular momentum anomalies which arise from changes in total ocean mass or from changes in ocean mass distribution, e.g., related to sea level rise (Chen et al. 2013). The OAM motion term includes angular momentum anomalies due to changes in ocean velocities, e.g., in the Antarctic Circumpolar Current (Brosche and Sündermann 1985).
Earth rotation excitation due to changes in ocean mass (black line) and currents (red line). Dimensionless effective angular...
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References and Reading
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Thomas, M., Saynisch-Wagner, J. (2022). Earth Rotation, Excitation, Oceanic, Non-tidal. In: Sideris, M.G. (eds) Encyclopedia of Geodesy. Encyclopedia of Earth Sciences Series. Springer, Cham. https://doi.org/10.1007/978-3-319-02370-0_107-1
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