Near-real-time surface ocean velocities derived from HF-radar stations located along coastal waters of North Slope Alaska, Gulf of Alaska, Puerto Rico/Virgin Islands, eastern U.S./Gulf of America, Hawaii, Great Lakes, and western U.S.

This dataset contains near-real-time ocean surface velocities, also known as total vector velocities, derived from high-frequency (HF) radar stations. The velocities are arranged in a horizontal latitude/longitude grid. Measured velocities are indicative of the upper 0.3 - 2.5 meters of the ocean depending on the operating frequency of the HF-radar and the vertical velocity profile of the water column. Data files are in NetCDF format following the CF (Climate and Forecast) Metadata Conventions. Velocities are reported in CF variables surface_eastward_sea_water_velocity and surface_northward_sea_water_velocity.

The National Data Buoy Center (NDBC) – in collaboration with the Scripps Institution of Oceanography through June 2025 and thereafter with NOAA’s National Environmental Satellite, Data, and Information Service (NESDIS) – assembles the data from the Integrated Ocean Observing System (IOOS) Surface Currents Program’s HF-Radar National Network and submits the data on a monthly basis to NOAA’s National Centers for Environmental Information (NCEI).

Remote sensing of ocean surface velocity from shore-based HF-radar sensors bridges the operational observational gap between point samples obtained from in-situ sampling and synoptic scale relatively low resolution data obtained from satellites by providing continuous mesoscale coverage at relatively high resolution near the coast.