Journal Highlights

Using magnetic field data to infer aspects of ocean circulation

Editor’s Highlight—

 

Conductive ocean water, when it moves through Earth’s ambient magnetic field, generates secondary electric field and magnetic fields. The poloidal part of the induced magnetic field can be observed outside the ocean at remote observatories and at satellites. It then follows that the ocean flow can be sensed from magnetic observations. While magnetic fields generated by tides and tsunamis are routinely observed in satellite and ground observatory data, the ocean circulation generated magnetic field has not be observed outside the ocean. This paper does not find these signals either but it does answer a hypothetical question about whether satellite observations of ocean circulation magnetic signals can be used to improve ocean circulation models. The authors find that with a very simple noise structure in the simulated satellite data, the assimilation results up to 7% improvements in ocean flow recovery, with regional enhancements and issues. This study provides important groundwork for uniting geomagnetism and physical oceanography. The idea of using magnetic field data to infer aspects of ocean circulation in a data assimilation context is innovative and potentially very useful, given the dearth of ocean observations and the urgent need to improve our understanding of the impact of climate change on global ocean circulation.