Instrument: IRIS (CRISTAL)
Interferometric Radar altimeter for Ice and Snow
To measure and monitor the variability of ice elevation and thickness in polar regions.
Dual-frequency radar altimeter: Ku-band around 13.5 GHz (bandwidth 500 MHz) and Ka-band around 35.75GHz (bandwidth 500 MHz). Along-track SAR capability for high spatial resolution. Two cross-track aligned antennas implementing interferometry to enlarge the swath and capture elevation changes.
Follow-on of the CryoSat SIRAL mission, with improved characteristics (main: dual-band).
No scanning. Several operating modes possible, depending on the target area.
10 km IFOV. When used in SAR mode, the along-track resolution is 80 m.
Coverage / Cycle
Global coverage on high latitudes in 1 month
Flown on an R&D satellite
≥2027-02 to ≥2034
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
Earth observation instrument Active and radio-occultation sensor Radar altimeter
Subcomponent 1 Wide-swath radar altimeter Subcomponent 2 Interferometric radar altimeter [for wide-swath]
Primary mission objectives
Ice sheet topography Sea-ice elevation Sea-ice thickness Secondary mission objectives Coastal sea level (tide) Ocean dynamic topography
Opportunity objectives Geoid Gravity field Significant wave height Wind speed (near surface) Show all Show fewer
Tentative Evaluation of Measurements
The following list indicates which measurements can
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
Variable Relevance for measuring this variable Operational limitations Explanation
Coastal sea level (tide) 1 - primary Infrequent coverage. Single-frequency Ka-band radar altimeter with large swath for mapping
Geoid 2 - very high Infrequent coverage.. Long time series needed. Geoid derived from multi-temporal analysis of radar altimetry data
Gravity field 4 - fair Partial information (geoid). Gravity field derived from multi-temporal analysis of radar altimetry data
Ice sheet topography 3 - high Along-track only.. Infrequent coverage. Ka-band radar altimeter
Ocean dynamic topography 1 - primary Infrequent coverage.. Long time for mapping. Single-frequency Ka-band radar altimeter with large swath for mapping
Sea-ice elevation 3 - high Infrequent coverage. The large swath helps measuring the elevation of the ice border over the sea level
Sea-ice thickness 3 - high Infrequent coverage.. Change detection only. The large swath helps measuring the elevation of the ice border over the sea level. Thickness inferred
Significant wave height 1 - primary Infrequent coverage. The large swath enables more frequent global coverage
Wind speed (near surface) 4 - fair Over sea only.. Infrequent coverage. Improved coverage associated to better resolution, that implies better accuracy