International Satellite to Track Impacts of Small Ocean Currents

Launching in November 2022, SWOT will collect data on ocean heights to study currents and eddies up to five times smaller than have been previously detectable.

Observing the ocean at relatively small scales will help scientists assess its role in moderating climate change.

The planet's largest storehouse of atmospheric heat and carbon, the ocean has absorbed more than 90% of the heat trapped by human-caused greenhouse gas emissions.

These flows are small relative to currents such as the Gulf Stream and the California Current, but researchers estimate that in the aggregate they transfer up to half the heat and carbon from surface waters to the ocean's depths.

Thinking Small Existing satellites can't detect smaller-scale currents and eddies, limiting research into how those features interact with each other and with larger-scale flows.

In addition to helping researchers study the climate impacts of small currents, SWOT's ability to "See" smaller areas of Earth's surface will allow it to collect more precise data along coastlines, where rising ocean levels and the flow of currents can have immediate impacts on land ecosystems and human activity.

So how will measuring ocean height lead to better knowledge of currents and eddies?

Systems of currents hundreds of miles wide flow around broad expanses of the ocean.

Filling in the Gaps By measuring ocean heights down to 0.16-inch increments, as well as their slopes, SWOT's two Ka-band Radar Interferometer antennas will help researchers discern currents and eddies as small as 12 miles across.

Compared with the fast weather fluctuations of the atmosphere, the slowly varying ocean exhibits strong persistence, or "Memory", meaning the ocean temperature tomorrow is likely to look a lot like it does today, with only slight changes.