BackForwardInstrument:  IRIS (X-Sat) 

Instrument details
Acronym IRIS (X-Sat)
Full name Iris
Purpose High-resolution land and vegetation observation
Short description 3 VIS/NIR channels [see detailed characteristics below]
Background Consolidated technology
Scanning Technique Pushbroom, swath 50 km possible to be addressed in a field-of-regard of 1170 km
Resolution 12 m
Coverage / Cycle Global coverage in 2 months, or progressively less by strategic pointing
Mass 12 kg Power 25 W Data Rate

 

Providing Agency NTU
Instrument Maturity Flown on an R&D satellite
Utilization Period: 2011-06-16 to 2019
Last update: 2020-01-06
Detailed characteristics
Central wavelength Spectral interval SNR @ specified albedo
0.560 μm 0.52 - 0.60 μm 100 @ ….. % albedo
0.660 μm 0.63 - 0.69 μm 100 @ ….. % albedo
0.825 μm 0.76 - 0.89 μm 100 @ ….. % albedo
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
  • Passive optical radiometer or spectrometer
  • High resolution optical imager
Mission objectives
Primary mission objectives
  • Biomass
  • Fraction of vegetated land
  • Land cover
  • Leaf Area Index (LAI)
  • Normalised Difference Vegetation Index (NDVI)
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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
Biomass5 - marginalCloud sensitive.. Index only.. Infrequent coverage.. Daylight only.VIS and NIR channels. Biomass inferred from NDVI
Cloud cover5 - marginalInfrequent coverage.. Daylight only.VIS and NIR channels
Cloud optical depth4 - fairLow-density cloud only.. Infrequent coverage.. Daylight only.VIS and NIR channels
Fire fractional cover2 - very highCloud sensitive.. Daylight only.VIS channels with high resolution for boundary detection
Fraction of vegetated land2 - very highCloud sensitive.. Daylight only.VIS and NIR channels
Glacier cover4 - fairCloud sensitive.. Long time for mapping.. Daylight only.VIS and NIR channels
Glacier topography5 - marginalCloud sensitive.. Long time for mapping.. Daylight only.VIS channel(s) and cross-track steering capability for stereoscopy between images from neighbour orbits
Ice sheet topography5 - marginalCloud sensitive.. Long time for mapping.. Daylight only.VIS channel(s) and cross-track steering capability for stereoscopy between images from neighbour orbits
Land cover2 - very highCloud sensitive.. Daylight only.VIS and NIR channels
Land surface topography5 - marginalCloud sensitive.. Long time for mapping.. Daylight only.VIS channel(s) and cross-track steering capability for stereoscopy between images from neighbouring orbits
Leaf Area Index (LAI)4 - fairCloud sensitive.. Daylight only.. Infrequent coverage.VIS and NIR channels. LAI inferred from NDVI
Normalised Difference Vegetation Index (NDVI)2 - very highCloud sensitive.. Infrequent coverage.VIS and NIR channels
Photosynthetically Active Radiation (PAR)5 - marginalCloud sensitive.. Infrequent coverage.VIS channels, range undersampled
Sea-ice cover5 - marginalCloud sensitive.. Daylight only.VIS and NIR (for contour enhancement) channels
Short-wave cloud reflectance5 - marginalInfrequent coverage.VIS and NIR channels. Unsuitable dynamic range (saturation)
Snow cover4 - fairCloud sensitive.. Infrequent coverage.. Daylight only.VIS and NIR channels
Soil moisture at surface5 - marginalCloud sensitive.. Index only.. Infrequent coverage.. Daylight only.VIS and NIR channels. Soil moisture inferred from differential brightness
Soil type2 - very highCloud sensitive.. Daylight only.VIS and NIR channels
Upward short-wave irradiance at TOA5 - marginalSpectral interpolation needed.. Information on BRDF needed.. Infrequent coverage.VIS and NIR channels
Vegetation type3 - highCloud sensitive.. Daylight only.VIS and NIR channels
Aerosol volcanic ash5 - marginalCloud sensitive.. Infrequent coverage.. Daylight only.VIS and NIR channels
Aerosol volcanic ash Total Column5 - marginalCloud sensitive.. Infrequent coverage.. Daylight only.VIS and NIR channels