Marine Magnetism

The animation of ocean tide displacement. The color bar for ocean tide displacement. The animation of ocean magnetic fields synthesized by a simulation model. The animation of ocean magnetic fields observed by satellites. The color bar for ocean magnetic fields. Earth’s magnetic field is built up from many contributing sources ranging from the planet’s core to the magnetosphere in space. Untangling and identifying the different sources allows geomagnetic scientists to gather information about the individual processes that combine to create the full field.One contributor is the ocean. But how do the tides affect Earth’s magnetic field? Seawater is an electrical conductor, and therefore interacts with the magnetic field. As the tides cycle around the ocean basins, the ocean water essentially tries to pull the geomagnetic field lines along. Because the salty water is a good, but not great, conductor, the interaction is relatively weak. The strongest component is from the regular lunar tide that happens about twice per day (actually 12.42 hours). Other contributions come from ocean swell, eddies, and even tsunamis.The strength of the interaction also depends on the temperature of the ocean water. Scientists are now able to determine how much heat is being stored in the entire ocean, from wave top to sea floor by observations of the Earth's magnetic field. Related pages

As Earth warms, much of the extra heat is stored in the planet’s ocean – but monitoring the magnitude of that heat content is a difficult task. A surprising feature of the tides could help, however. Scientists at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, are developing a new way to use satellite observations of magnetic fields to measure heat stored in the ocean.Music: War Torn by Brad Smith [BMI] Complete transcript available.Watch this video on the NASA Goddard YouTube channel. As Earth warms, much of the extra heat is stored in the planet’s ocean – but monitoring the magnitude of that heat content is a difficult task. A surprising feature of the tides could help, however. Scientists at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, are developing a new way to use satellite observations of magnetic fields to measure heat stored in the ocean.The method depends on several geophysical features of the ocean. Seawater is a good electrical conductor, so as the saltwater sloshes around the ocean basins it causes slight fluctuations in Earth’s magnetic field lines. The ocean flow attempts to drag the field lines along. The resulting magnetic fluctuations are relatively small, but have been detected from an increasing number of events including swell, eddies, tsunamis, and tides.The magnetic fluctuations of the tides depend on the electrical conductivity of the water – and the electrical conductivity of the water depends on its temperature. This new method could be the first to provide global ocean heat measurements, integrated over all depths, using satellite observations. For More InformationSee [https://www.nasa.gov/feature/goddard/2016/earth-s-magnetic-fields-could-track-ocean-heat-nasa-study-proposes](https://www.nasa.gov/feature/goddard/2016/earth-s-magnetic-fields-could-track-ocean-heat-nasa-study-proposes) Related pages

Seawater is an electrical conductor, and therefore interacts with the magnetic field. As the tides cycle around the ocean basins, the ocean water essentially tries to pull the geomagnetic field lines along.Because the salty water is a good, but not great, conductor, the interaction is relatively weak. Scientists at NASA Goddard Space Flight Center are developing improved methods to isolate the signal from ocean tides and use that information to determine the heat content of the ocean.Music: "Memory Of A Lifetime" by J Ehrlich [SESAC], Jean-Christophe Beck [BMI]Complete transcript available.Watch this video on the NASA Goddard YouTube channel. Earth’s magnetic field is built up from many contributing sources ranging from the planet’s core to the magnetosphere in space. Untangling and identifying the different sources allows geomagnetic scientists to gather information about the individual processes that combine to create the full field. One contributor is the ocean, although it is a small contributor. From that isolated contribution, scientists at NASA Goddard Space Flight Center have developed a way to determine the heat content of the ocean. But how do the tides affect Earth’s magnetic field? Seawater is an electrical conductor, and therefore interacts with the magnetic field. As the tides cycle around the ocean basins, the ocean water essentially tries to pull the geomagnetic field lines along. Because the salty water is a good, but not great, conductor, the interaction is relatively weak. The strongest component is from the regular lunar tide that happens about twice per day (actually 12.42 hours). Other contributions come from ocean swell, eddies, and even tsunamis.The strength of the interaction depends on the temperature of the ocean water, and scientists are now able to determine how much heat is being stored in the entire ocean, from wave top to sea floor. For More InformationSee [https://www.nasa.gov/feature/goddard/2016/earth-s-magnetic-fields-could-track-ocean-heat-nasa-study-proposes](https://www.nasa.gov/feature/goddard/2016/earth-s-magnetic-fields-could-track-ocean-heat-nasa-study-proposes) Related pages