Along-track significant wave height, wind speed and sea level anomaly from multiple altimeters

The Radar Altimeter Database System (RADS) is employed is employed at NESDIS/STAR as a enterprise multi-mission algorithm providing consistent sea level anomaly, waves, and ocean surface wind speed products. RADS is a joint effort of the NOAA Laboratory for Satellite Altimetry (LSA), EUMETSAT, and Department of Earth Observation and Space Systems (DEOS) at the Delft University of Technology to establish a harmonized, validated, and cross-calibrated sea level data base from satellite altimeter data. RADS was designed primarily as a database tool for expert altimetry users but through NOAA CoastWatch and LSA training materials, may have appeal at both expert and entry levels: advisory councils, water management authorities, teachers, and students.

RADS homogenizes data from multiple missions which in turn are used to generate Level-2P products for operational users, including data assimilation at NOAA and the US Navy (e.g. the Global Real-Time Ocean Forecast System (Global RTOFS) and the West Coast Operational Forecast System) and Level-2P and Level-3 products distributed through NOAA CoastWatch (Sea Level Anomaly and along-track altimetry). It is also used as calibration/validation platform.

The database is a collection of continually updated NetCDF datasets. Geophysical Data Records and associated corrections are processed and stored in homogenized NetCDF pass files. Near real-time processing is done two times per day at NOAA for the following missions: Jason-3, Sentinel-3A, Sentinel-3B, AltiKa/SARAL, and CryoSat-2. Reprocessing is done jointly with EUMETSAT. These files can then be used to generate products using the RADS data utilities.

Variables used within RADS include (not all inclusive):

• Time, latitude, longitude
• Sea level (anomaly with respect to a mean sea surface, or absolute dynamic topography)
• Ocean surface windspeed
• Wave height
• Multiple options for geophysical corrections (tide models, path delays)
• Multiple options for instrument corrections
• Radiometer brightness temperatures
• Radar range, orbital altitude and rate
• Bathymetry, sea surface temperatures
• Engineering and geophysical flags