BackForwardInstrument:  POLDER 

Instrument details
Acronym POLDER
Full name Polarization and Directionality of the Earth’s Reflectances
Purpose Aerosol, ocean colour, vegetation, Bidirectional Reflectance Distribution Function (BRDF)
Short description 9 wavelengths, with 3 polarisations at 3 wavelengths; total: 15 channels [see detailed characteristics below]
Background New development
Scanning Technique 242 x 274 CCD arrays, 2400 km swath, each earth’s spot viewed from more directions as satellite moves
Resolution 6.5 km
Coverage / Cycle Near-global coverage every day in daylight.
Mass 32 kg Power 50 W Data Rate 883 kbps

 

Providing Agency CNES
Instrument Maturity Flown on an R&D satellite
Utilization Period: 1996 to 2013-12-18
Last update: 2012-09-12
Detailed characteristics
Central wavelength Bandwidth No. of pol. SNR at specified input spectral radiance
443.5 nm 13.4 nm - 200 @ 61.9 W m-2 sr-1 µm-1
490.9 nm 16.3 nm three 200 @ 63.2 W m-2 sr-1 µm-1
563.8 nm 15.4 nm - 200 @ 58.1 W m-2 sr-1 µm-1
669.9 nm 15.1 nm - 200 @ 48.7 W m-2 sr-1 µm-1
762.9 nm 10.9 nm three 200 @ 38.9 W m-2 sr-1 µm-1
762.7 nm 38.1 nm - 200 @ 38.9 W m-2 sr-1 µm-1
863.7 nm 33.7 nm - 200 @ 30.8 W m-2 sr-1 µm-1
907.1 nm 21.1 nm three 200 @ 27.5 W m-2 sr-1 µm-1
1019.6 nm 17.1 nm - 200 @ 22.6 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
  • Moderate resolution optical imager
Mission objectives
Primary mission objectives
  • Aerosol Optical Depth
  • Aerosol column burden
  • Aerosol effective radius
  • Aerosol mass mixing ratio
  • Aerosol type
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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
Aerosol column burden1 - primaryCloud sensitive.. Daylight only.VIS (with narrow bandwidth) and NIR channels including 760 nm, with multi-angle viewing and polarimetry for more aerosol types, also over land
Aerosol effective radius4 - fairCloud sensitive.. Daylight only.VIS (with narrow bandwidth) and NIR channels including 760 nm for high-level aerosol, with multi-angle viewing and polarimetry for several aerosol types, also over land
Aerosol mass mixing ratio3 - highCloud sensitive.. Daylight only.VIS (with narrow bandwidth) and NIR channels including 760 nm for high-level aerosol, with multi-angle viewing and polarimetry for several aerosol types, also over land
Aerosol Optical Depth1 - primaryCloud sensitive.. Daylight only.VIS (with narrow bandwidth) and NIR channels including 760 nm for high-level aerosol, with multi-angle viewing and polarimetry for more aerosol types, also over land
Aerosol type3 - highCloud sensitive.. Daylight only.VIS (with narrow bandwidth) and NIR channels including 760 nm foe high-level aerosol, with multi-angle viewing and polarimetry for more aerosol types, also over land
Biomass5 - marginalCloud sensitive.. Index only.. Daylight only.VIS and NIR channels. Biomass inferred from NDVI
Cloud cover5 - marginalDaylight only.VIS and NIR channels
Cloud drop effective radius4 - fairAt cloud top.. Daylight only.VIS and NIR channels and different viewing angles (for differentiation).
Cloud ice effective radius4 - fairAt cloud top.. Daylight only.VIS and NIR channels with different viewing angles (for differentiation).
Cloud optical depth3 - highLow-density cloud only.. Daylight only.VIS and NIR channels with different viewing angles
Cloud top height5 - marginalDaylight only.NIR channels to estimate the total-column O2 above the cloud top as measured around 760 nm
Cloud type3 - highDaylight only.VIS and NIR channels viewing under more angles
Colour Dissolved Organic Matter (CDOM)4 - fairCloud sensitive.. Daylight only.A few narrow-bandwidth VIS channels, suitable for a few water types, mainly in open ocean
Downward short-wave irradiance at Earth surface5 - marginalCloud sensitive.. Highly indirect.VIS and NIR channels
Earth surface albedo1 - primaryCloud sensitive.VIS channels with many viewing angles to account for anisotropic reflectivity
Earth surface short-wave bidirectional reflectance2 - very highCloud sensitive.VIS and NIR range with many different viewing angles
Fire fractional cover5 - marginalCloud sensitive.. Coarse spatial resolution.. Daylight only.VIS channels
Fraction of Absorbed PAR (FAPAR)1 - primaryCloud sensitive.VIS channels including Red at 700 nm, with more viewing angles
Leaf Area Index (LAI)5 - marginalCloud sensitive.. Daylight only.VIS and NIR channels. LAI inferred from NDVI
Normalised Difference Vegetation Index (NDVI)2 - very highCloud sensitive.VIS and NIR channels
Ocean chlorophyll concentration 4 - fairCloud sensitive.. Daylight only.A few narrow-bandwidth VIS channels, suitable for a few water types, mainly in open ocean
Ocean Diffuse Attenuation Coefficient (DAC)4 - fairCloud sensitive.. Daylight only.A few narrow-bandwidth VIS channels, suitable for a few water types, mainly in open ocean
Ocean suspended sediments concentration4 - fairCloud sensitive.. Daylight only.A few narrow-bandwidth VIS channels, suitable for a few water types, mainly in open ocean
Oil spill cover2 - very highCloud sensitive.. Daylight only.VIS channels with narrow bandwidth, with different viewing angles
Photosynthetically Active Radiation (PAR)2 - very highCloud sensitive.VIS channels, range undersampled; multi-viewing capability for irradiance reconstruction
Sea-ice cover5 - marginalCloud sensitive.. Daylight only.VIS and NIR (for contour enhancement) channels
Short-wave cloud reflectance2 - very highNo specific limitation.VIS and NIR channels with multi-viewing and multi-polarisation capabiliy to account for anisotropical reflectance
Snow cover5 - marginalCloud sensitive.. Daylight only.VIS and NIR channels
Soil moisture at surface5 - marginalCloud sensitive.. Index only.. Daylight only.VIS and NIR channels. Soil moisture inferred from differential brightness
Integrated Water Vapour (IWV)5 - marginalCloud sensitive.. Daylight only.NIR channels in the ro-sigma-tau band of water vapour around 940 nm
Upward short-wave irradiance at TOA3 - highSpectral interpolation needed.VIS and NIR channels with multi-viewing and multi-polarisation capability to account for anisotropical reflectance
Aerosol volcanic ash3 - highCloud sensitive.. Daylight only.VIS and NIR channels including 760 nm, with multi-angle viewing and polarimetry for accurate ash identification, also over land
Aerosol volcanic ash (Total column)1 - primaryCloud sensitive.. Daylight only.VIS and NIR channels including 760 nm, with multi-angle viewing and polarimetry for accurate ash identification, also over land