CEOS EO HANDBOOK – MEASUREMENT INSTRUMENTS
Measurements > Ocean >
Ocean wave height and spectrum >
Significant wave height


Measurement Definition*: Average amplitude of the highest 30 of 100 waves - Physical unit: [ m ] - Accuracy unit: [ m ].

Thematic Links
InstrumentStatus/
Accuracy
Instrument DescriptionMeasurement TechnologyTimeline
ALT
Radar Altimeter
Operational
Global ocean topography, sea level and gravity field measurements.Radar altimeter
AltiKa
Ka-band Altimeter
Operational
Sea surface height.Radar altimeter
C-Band SAR
C-Band Synthetic Aperture Radar
Operational
Marine core services, land monitoring and emergency services. Monitoring sea ice zones and arctic environment. Surveillance of marine environment, monitoring land surface motion risks, mapping of land surfaces (forest, water and soil, agriculture), mapping in support of humanitarian aid in crisis situations.Imaging radar (SAR)
POSEIDON-3B Altimeter
Positioning Ocean Solid Earth Ice Dynamics Orbiting Navigator (Single frequency solid state radar altimeter)
Operational
Nadir viewing sounding radar for provision of real-time high precision sea surface topography, ocean circulation and wave height data.Radar altimeter
POSEIDON-3C Altimeter
Positioning Ocean Solid Earth Ice Dynamics Orbiting Navigator (Single frequency solid state radar altimeter)
Operational
Nadir viewing sounding radar for provision of real-time high precision sea surface topography, ocean circulation and wave height data.Radar altimeter
Poseidon-4 Altimeter
Poseidon-4 SAR Radar Altimeter
Operational
Nadir viewing sounding radar for provision of real-time high-precision sea surface topography, ocean circulation and wave height data.Radar altimeter
SAR (RADARSAT-2)
Synthetic Aperture Radar (SAR) C band
Operational
All-weather images of ocean, ice and land surfaces. Used for monitoring of coastal zones, polar ice, sea ice, sea state, geological features, vegetation and land surface processes.Imaging radar (SAR)
SAR (RCM)
Synthetic Aperture Radar (SAR) C band
Operational
All-weather, C-band data to support ecosystem monitoring, maritime surveillance and disaster management.Imaging radar (SAR)
SGR-ReSI-CDHS
Space GNSS Receiver - Remote Sensing Instrument, CoreDHS avionics
Operational
Ocean winds, waves, soil moisture, flooding, ice, snow. Similar to SGR-ReSI-Z, but with a smaller Zynq, and only supports 2 RF channels, only allowing collection of single frequency and single polarisation.n/a
SRAL
SAR Radar Altimeter
Operational
Marine and land services.Radar altimeter
SWIM
Surface Waves Investigation and Monitoring
Operational
Ku-band Real-aperture radar (RAR) system, multi-incindence beams(0-10°) and azimuth scanning. Measurement of 2D ocean waves spectrumn/a
IRIS
Interferometric Radar Altimeter for Ice and Snow
Being developed
Ku-band Interferometric Synthetic Aperture Radar Altimeter (with added Ka-band channel for snow depth retrieval and in combination with AMR-CR MW Radiometer for ice&snow classification and wet troposphere correction) to cover the needs for continuous monitoring of sea ice thickness and land ice elevation measurement after Cryosat-2, with enhanced performance.Radar altimeter
Poseidon-5 Altimeter
Poseidon-5 SAR Radar Altimeter
Being developed
 Radar altimeter
SAOOH
Swath Altimeter for Oceanography and Operational Hydrology
Being developed
 n/a
SGR-ReSI-Z
Space GNSS Receiver - Remote Sensing Instrument (Zynq based)
Being developed
Ocean winds, waves, soil moisture, flooding, ice, snown/a
* Description adapted from WMO.