Hurricane Erin cloud imagery from GOES-19) and ocean surface vector winds from ASCAT-C. Credit: NOAA/CIRA
The ocean is a vast, interconnected system that covers about seventy percent of the Earth’s surface. Satellites are essential for observing this environment, supporting marine transportation, weather monitoring, and coastal safety. A particularly important measurement is ocean surface vector winds (OSVW), which help oceanographers and meteorologists understand and predict the short- and long-term ocean processes that drive some of Earth's system. Winds transfer momentum for the ocean surface, shaping everything from individual waves to hurricanes.
NESDIS’s Center for Satellite Applications and Research (STAR) works with partner agencies to provide a suite of satellite-derived ocean wind data and products, using multiple types of sensors:
- Microwave sensors: Observe the ocean through clouds and storms.
- Scatterometers: Measure ocean surface wind speed and direction.
- Satellite example: The European Organisation for the Exploitation of Meteorological Satellites’ Advanced Scatterometer (EUMETSAT’s ASCAT).
Image captured in Caribbean. Credit: NOAA
- Radiometers: Measure wind speed, rain rate, water vapor, and sea surface temperature.
- Satellite example: Japan Aerospace Exploration Agency’s Advanced Microwave Scanning Radiometer 2 (JAXA’s AMSR-2)
Image captured at U.S. West Coast
- Altimeters: Measure ocean surface height and capture wind and wave information.
- Satellite example: The European Space Agency’s Sentinel-3A/B oceanography satellites.
- Synthetic Aperture Radar (SAR): Produce the highest-resolution imagery, capable of detecting the strongest hurricane winds.
STAR’s Targeted Field Campaigns
To ensure decision makers receive trusted, high-quality ocean wind data, STAR integrates satellite observations with targeted field campaigns.
Areial imagery from inside the eye of Hurricane Erin on the NOAA P-3 Hurricane Hunter plane. These images were taken about the same time as satellite data was gathered.
During hurricanes, NOAA’s P-3 Hurricane Hunter aircraft fly directly into storms to collect in situ data with instruments such as the Imaging Wind and Rain Airborne Profiler (IWRAP) and Ka-band Interferometric Altimeter (KaIA) in collaboration with the University of Massachusetts Amherst and Tomorrow.io.
SAR wind validation during Hurricane Erin flights, August 2025. Credit: NOAA
The figure below illustrates three-dimensional atmospheric wind speeds and two-dimensional ocean surface wind fields collected by combining IWRAP and the Hurricane Forecast Analysis System model measurements during a flight into Hurricane Lee in 2023.
STAR is also testing and validating a next-generation radar system called the Rain, Ocean, and Atmosphere Radar System (ROARS) with Agile Radar on both the NOAA P-3 planes. ROARS combines the retrieval capabilities of IWRAP and KaIA into a single compact instrument, providing the highest-resolution observations of atmospheric winds in the hurricane to date. These improved observations enable the National Weather Service’s Ocean Prediction Center and National Hurricane Center to analyze storms with greater confidence and issue timely marine and tropical cyclone warnings that help protect lives, property, and commerce.
Together, these satellite sensors and targeted field campaigns provide a global view of the winds that drive weather hazards, from tropical cyclones to winter storms. As the demand for accurate, timely marine data grows, STAR continues to advance its ocean wind products. These enhanced datasets and products also support marine safety, search and rescue, oil spill response, and economic activities that depend on accurate, reliable ocean conditions.