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Schlagwörter:
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Zusammenfassung:
The recent advent of new high-resolution datasets of electromagnetic induction allows novel combinations of
observations and models. The ocean induced magnetic field provides the potential to indirectly observe the ocean
general circulation and may be utilized by data assimilation techniques. The modelling of the ocean induced
magnetic field is affected by various uncertainties that originate from errors in the input data and from the applied
model itself. The amount of aggregated uncertainties and their effect on the modelling of electromagnetic induction
in the ocean is unknown. However, the knowledge of model uncertainties is essential for many research questions.
To investigate the uncertainty in the modelling of motional induction, ensemble simulations with an ocean general
circulation model and an electromagnetic induction model are performed on the basis of different error scenarios.
This approach allows to estimate both the spatial distribution and temporal variation of the uncertainty. The largest
uncertainty in the motionally induced magnetic field occurs in the area of the Antarctic Circumpolar Current. Local
maxima reach values of up to 0.7 nano Tesla (nT). The estimated global annual mean uncertainty in the motionally
induced magnetic field ranges from 0.1 to 0.4 nT. The relative amount of uncertainty reaches up to 30 % of the
induced magnetic signal strength with largest values in regions in the northern hemisphere. The major source
of uncertainty is found to be introduced by the wind stress from the atmospheric forcing of the ocean model. In
addition, the temporal evolution of the uncertainty in the motionally induced magnetic field shows distinct seasonal
variations. Specific regions are identified which are robust with respect to the introduced uncertainties.
