BackForwardInstrument:  WFI 

Instrument details
Acronym WFI
Full name Wide Field Imager
Purpose High-resolution land and vegetation observation
Short description 2 channels in VIS and NIR [see detailed characteristics below]
Background Consolidated technology
Scanning Technique Pushbroom. 3456 pixel/line, swath 890 km
Resolution 260 m
Coverage / Cycle Global coverage in 5 days
Mass 8 kg Power 8 W Data Rate 1.1 Mbps

 

Providing Agency CAST
Instrument Maturity Flown on an R&D satellite
Utilization Period: 2000 to 2010-05-16
Last update: 2017-03-28
Detailed characteristics
Central wavelength Spectral interval SNR @ specified albedo
0.66 µm 0.63 - 0.69 µm 8 @ 2 % albedo
0.83 µm 0.77 - 0.89 µm 16 @ 4 % 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 depth5 - marginalLow-density cloud only.. Infrequent coverage.. Daylight only.VIS and NIR channels
Fraction of vegetated land2 - very highCloud sensitive.. Daylight only.VIS and NIR channels
Glacier cover5 - marginalCloud 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 cover3 - 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)5 - marginalCloud 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
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 cover5 - marginalCloud 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 type5 - marginalCloud 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 type4 - fairCloud sensitive.. Daylight only.VIS and NIR channels
Aerosol volcanic ash5 - marginalCloud sensitive.. Infrequent coverage.. Daylight only.VIS and NIR channels
Aerosol volcanic ash (Total column)5 - marginalCloud sensitive.. Infrequent coverage.. Daylight only.VIS and NIR channels