Magnetic fields found to yield accurate ocean temperatures

Posted 12 January 2017

EarthA new use of satellite technology could provide scientists with accurate measurements of ocean temperatures through the observation of oceanic flows.

Scientists at NASA's Goddard Space Flight Center in the US are beginning to use satellite observations of magnetic fields from ocean flows to measure heat stored in the ocean, said Goddard research scientist Robert Tyler.

"The recent launch of the European Space Agency's Swarm satellites and their magnetic survey is providing unprecedented observational data of the magnetic fluctuations," Tyler said. 

"With this comes new opportunities."

If successful, it would be the first time worldwide measurements of ocean temperatures at all depths were measured using satellite observations. 

Through the use of high-resolution data from the Swarm satellites, researchers can identify magnetic fluctuations from regular ocean flows. Seawater is an effective electrical conductor, so as saltwater flows around ocean basins it causes slight fluctuations in Earth's magnetic field lines, Tyler said. 

The magnetic fluctuations of the tides are dependant on the electrical conductivity of the water, which in turn relies on the water’s temperature. 

The ability to measure the temperature of the ocean would be increasingly useful, with the effects of rising ocean temperatures a cause for environmental concern, said Catherine Walker, an ice scientist at NASA's Jet Propulsion Laboratory.

"These big influxes of warm water come onto the continental shelf in some years and affect the rate at which ice melts," Walker said.

Rising ocean temperatures will also have a significant effect on microscopic phytoplankton communities.

"Increased stratification in the ocean due to increased heating is going to lead to winners and losers within the phytoplankton communities," said Stephanie Schollaert Uz, a scientist at Goddard.

Goddard scientists will continue to attempt to improve the satellite sensing technique in order to improve future understanding of the ripple effects of rising ocean temperatures