Realizing Simultaneous Ocean Wind and Current Measurements
In 2016, an airborne instrument developed at the Jet Propulsion Lab called DopplerScatt conducted several validation flights onboard a Department of Energy B200 aircraft. The Ka-band Doppler scatterometer demonstrated its ability to take simultaneous measurements of ocean surface vector winds and currents – a new science capability that has helped improve our understanding of air-sea interactions and their influence on Earth’s climate.
While prior instruments measured ocean currents or wind individually, DopplerScatt could do both, providing a new perspective on sea surface properties and air-sea interactions.
DopplerScatt utilizes a spinning transmitter that bounces radar off the ocean’s surface to take measurements in multiple directions at once. It calculates the Doppler effect of the return signal to determine speed and trajectory. Those measurements are combined with data from a scatterometer, which calculates wind speed and direction from the “scattering” of the radar signal by the roughness of the ocean surface.
By 2017, DopplerScatt was used on two airborne science campaigns alongside other instruments.
The Submesoscale Processes and Lagrangian Analysis on the Shelf (SPLASH) campaign led by the Consortium for Advanced Research on Transport of Hydrocarbon in the Environment (CARTHE), used DopplerScatt to investigate the movement of potential oil spills and leaks in the Gulf of Mexico.
DopplerScatt also participated in the Keck Institute for Space Studies Controlled, Agile, and Novel Ocean Network (CANON) campaign. It provided an overhead view of currents while autonomous, robotic vehicles and gliders gathered in situ data at various depths in Monterey Bay.
To date, DopplerScatt has logged over 350 flight hours on NASA aircraft, taking measurements and participating in science campaigns such as the Sub-Mesoscale Ocean Dynamics and Vertical Transport Experiment (S-MODE). While DopplerScatt will continue to be used on future NASA airborne science missions, the technology also lays the groundwork for an eventual spaceborne instrument, which would enable global measurements of ocean surface winds and water currents simultaneously for the first time.