NASA’s Surface Water and Ocean Topography (SWOT) satellite is revealing surprising insights into how small-scale ocean features can have large-scale impacts on Earth’s climate and marine ecosystems.
A joint mission with the French space agency CNES, and support from the Canadian and UK space agencies, SWOT is transforming how scientists understand vertical ocean circulation and its effects.
In a breakthrough NASA-led study, SWOT captured high-resolution, two-dimensional images of submesoscale eddies and waves—features just about a mile wide—uncovering their critical role in moving heat, nutrients, and carbon between the ocean’s depths and surface. These small but mighty currents, long underestimated, are now seen as vital components in maintaining the balance of the global climate and supporting marine life.
According to NASA’s Jet Propulsion Laboratory, SWOT is helping scientists see what was previously hidden.
These vertical currents, too fine for older satellite sensors and too broad for ship measurements, are now visible. “Vertical currents can bring heat from deep layers to the surface, warming the atmosphere,” said oceanographer Matthew Archer. SWOT tracked a submesoscale eddy in the Kuroshio Current of the Pacific Ocean and measured vertical movement reaching up to 14 meters per day—an important process that sustains surface ecosystems.
The satellite also monitored an internal solitary wave in the Andaman Sea, which carried twice the energy of a typical internal tide. Using sea surface height data, researchers can now infer slopes and fluid pressure, which helps calculate the strength of ocean currents and the energy or material being moved. “Force is the fundamental quantity driving fluid motion,” explained coauthor Jinbo Wang of Texas A&M University.
SWOT’s discoveries are already prompting scientists to rethink and update ocean models. “Now models must adapt to these small-scale features,” said Lee Fu from JPL. Data from SWOT is being fed into NASA’s ECCO ocean model, advancing understanding of how oceans influence weather patterns and climate.
With global snapshots every 21 days, SWOT marks a new era in Earth observation.