BackForwardInstrument:  WFI-2 

Instrument details
Acronym WFI-2
Full name Wide Field Imager - 2
Purpose High-resolution land and vegetation observation
Short description 4 channels in VIS and NIR [see detailed characteristics below]
Background Evolution of WFI on CBERS 1/2/2B
Scanning Technique Pushbroom, swath 866 km
Resolution 73 m
Coverage / Cycle Global coverage in 5 days
Mass 47 kg Power 70 W Data Rate 50 Mbps

 

Providing Agency CAST
Instrument Maturity Backed by strong heritage
Utilization Period: 2013-12-09 to ≥2023
Last update: 2020-01-07
Detailed characteristics
Central wavelength Spectral interval SNR @ specified input spectral radiance
Low signal High signal
0.555 µm 0.52 - 0.59 µm 31 @ 27.5 W m-2 sr-1 μm-1 48 @ 361 W m-2 sr-1 μm-1
0.66 µm 0.63 - 0.69 µm 25 @ 12.9 W m-2 sr-1 μm-1 47 @ 307 W m-2 sr-1 μm-1
0.83 µm 0.77 - 0.89 µm 26 @ 8.9 W m-2 sr-1 μm-1 47 @ 243 W m-2 sr-1 μm-1
1.65 µm 1.55 - 1.75 µm ..... @ ...... W m-2 sr-1 μm-1 ...... @ ...... W m-2 sr-1 μm-1
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
Biomass4 - fairCloud sensitive.. Index only.. Infrequent coverage.. Daylight only.VIS, NIR and SWIR channels. Biomass inferred from NDVI and LAI
Cloud cover5 - marginalInfrequent coverage.. Daylight only.VIS, NIR and SWIR channels
Cloud optical depth3 - highLow-density cloud only.. Infrequent coverage.. Daylight only.VIS, NIR and SWIR channels
Fire fractional cover2 - very highCloud sensitive.. Daylight only.VIS channels with high resolution for boundary detection
Fraction of vegetated land1 - primaryCloud sensitive.. Daylight only.VIS, NIR and SWIR channels
Glacier cover3 - highCloud sensitive.. Long time for mapping.. Daylight only.VIS, NIR and SWIR channels, screening ice from clouds
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 cover1 - primaryCloud sensitive.. Daylight only.VIS, NIR and SWIR 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)2 - very highCloud sensitive.. Daylight only.. Infrequent coverage.VIS, NIR and SWIR channels
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 cover4 - fairCloud sensitive.. Daylight only.VIS, NIR (for contour enhancement) and SWIR (for discrimination from clouds) channels
Short-wave cloud reflectance4 - fairInfrequent coverage.VIS, NIR and SWIR channels. Unsuitable dynamic range (saturation)
Snow cover1 - primaryCloud sensitive.. Infrequent coverage.. Daylight only.VIS, NIR and SWIR channels, enabling screening snow from clouds
Soil moisture at surface5 - marginalCloud sensitive.. Index only.. Infrequent coverage.. Daylight only.VIS, NIR and SWIR channels. Soil moisture inferred from differential brightness
Soil type1 - primaryCloud sensitive.. Daylight only.VIS, NIR and SWIR channels
Upward short-wave irradiance at TOA5 - marginalSpectral interpolation needed.. Information on BRDF needed.. Infrequent coverage.VIS, NIR and SWIR channels
Vegetation type2 - very highCloud sensitive.. Daylight only.VIS, NIR and SWIR channels
Aerosol volcanic ash5 - marginalCloud sensitive.. Infrequent coverage.. Daylight only.VIS, NIR and SWIR channels
Aerosol volcanic ash Total Column5 - marginalCloud sensitive.. Infrequent coverage.. Daylight only.VIS, NIR and SWIR channels