BackForwardInstrument:  RA 

Instrument details
Acronym RA
Full name Radar Altimeter
Purpose Ocean topography, significant wave height, wind speed on sea surface
Short description Single frequency (13.8 GHz)
Background Flown on ERS-1 (1991-2000) and ERS-2 (1995-2011)
Scanning Technique Nadir-only viewing, continuous sampling along track
Resolution 20 km IFOV
Coverage / Cycle Global coverage in 1 month for 30 km average spacing, or in 10 days for 100 km average spacing
Mass 96 kg Power 130 W Data Rate 15 kbps

 

Providing Agency ESA
Instrument Maturity Flown on operational programme
Utilization Period: 1991 to 2011-07-06
Last update: 2012-06-06
Detailed characteristics
Satellites this instrument is flying on

Note: a red tag indicates satellites no longer operational, a green tag indicates operational satellites, a blue tag indicates future satellites

Instrument classification
  • Earth observation instrument
  • Active and radio-occultation sensor
  • Radar altimeter
Mission objectives
Primary mission objectives
  • Geoid
  • Ocean dynamic topography
  • Significant wave height
Secondary mission objectives
  • Coastal sea level (tide)
  • Gravity field
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Tentative Evaluation of Measurements

The following list indicates which measurements can typically be retrieved from this category of instrument. To see a full Gap Analysis by Variable, click on the respective variable.

Note: table can be sorted by clicking on the column headers
VariableRelevance for measuring this variableOperational limitationsExplanation
Coastal sea level (tide)5 - marginalAlong-track only.Single-frequency Ku-band radar altimeter
Geoid2 - very highLong time series needed.. Along-track only.Geoid derived from multi-temporal analysis of radar altimetry data
Gravity field3 - highPartial information (geoid).. Along-track only.Gravity field derived from multi-temporal analysis of radar altimetry data
Ocean dynamic topography3 - highLong time for mapping.. Along-track only.Single-frequency Ku-band radar altimeter
Significant wave height4 - fairAlong-track only.Ku-band radar altimeter
Wind speed over the surface (horizontal)5 - marginalOver sea only.. Along-track only.Radar altimeter. Wind speed estimated from the intensity of the backscattered signals