BackForwardInstrument:  SIRAL 

Instrument details
Acronym SIRAL
Full name SAR Interferometer Radar Altimeter
Purpose Ice topography, ocean topography, significant wave height, wind speed on sea surface
Short description
  • Single frequency (13.575 GHz, bandwidth 350 MHz), with SAR capability along-track for high spatial resolution, and two cross-track aligned antennas implementing SAR interferometry to capture elevation changes
  • Instrument monitoring and calibration here
Background

First embarked on CryoSat, failed at launch
Scanning Technique

No scanning.  Several operating modes possible, depending on the target area
Resolution 15 km IFOV.  When used in SAR mode, the along-track resolution is 250 m
Coverage / Cycle Global coverage on high latitudes in 1 month
Mass 70 kg Power 149 W Data Rate 60 kbps, 12 Mbps (SAR), 24 Mbps (SAR interferometry)

 

Providing Agency ESA
Instrument Maturity Flown on an R&D satellite
Utilization Period: 2005 to 2028
Last update: 2024-09-09
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
WIGOS Subcomponents
  • Subcomponent 1
  • Wide-swath radar altimeters, and high altitude, inclined, high-precision orbit altimeters
  • Conventional radar altimeter
  • Subcomponent 2
  • Interferometric radar altimetry
  • Interferometric radar altimeter [for wide-swath]
Mission objectives
Primary mission objectives
  • Geoid
  • Ocean dynamic topography
  • Significant wave height
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
Note: * Primary mission objective.
VariableRelevance for measuring this variableOperational limitationsExplanation
Coastal sea level (tide)3 - highAlong-track only.Single-frequency Ku-band radar altimeter
Geoid*2 - very highLong time series needed.. Along-track only.Geoid derived from multi-temporal analysis of radar altimetry data
Gravity field4 - fairPartial information (geoid).. Along-track only.Gravity field derived from multi-temporal analysis of radar altimetry data
Ocean dynamic topography*3 - highLong time for mapping.. Along-track only.Single-frequency Ku-band radar altimeter
Sea-ice elevation2 - very highAlong-track only.Ku-band radar altimeter with along-track SAR capability for accurate ice border detection and differential ice-sea height measurement
Sea-ice thickness2 - very highChange detection only.. Along-track only.Ku-band radar altimeter with along-track SAR capability for accurate ice border detection and differential ice-sea height measurement. Thickness inferred by ice model
Significant wave height*2 - very highAlong-track only.Ku-band radar altimeter
Wind speed (near surface)5 - marginalOver sea only.. Along-track only.Radar altimeter. Wind speed estimated from the intensity of the backscattered signals