BackForwardInstrument:  SGLI 

Instrument details
Acronym SGLI
Full name Second-generation Global Imager
Purpose Ocean colour, vegetation indexes, aerosol
Short description 19-channel radiometer, 17 narrow-bandwidth in VIS/NIR/SWIR and two broadband in the Thermal IR.  Two channels with three polarisations [see detailed characteristics below]
Background Evolution of GLI flown on ADEOS-2 (2002-2003)
Scanning Technique VNIR: pushbroom; SWIR/TIR: whiskbroom   Swath 1150 km (VNIR and polarimetric channels) or 1400 km (SWIR and TIR channels). Cross-track: 3 CCD of 2000 pixels each of 250 m s.s.p. (non polarimetric channels) and 1 CCD of 1000 pixels of 1 km s.s.p. (polarimetric channels). Along-track tilting capability of ± 45° to avoid sunglint
Resolution 250 m to 1.0 km (see below)
Coverage / Cycle Global coverage in 3 days (in daylight)
Mass 400 kg Power 480 W Data Rate 139 Mbps

 

Providing Agency JAXA
Instrument Maturity Backed by strong heritage
Utilization Period: ≥2017 to ≥2027
Last update: 2012-10-10
Detailed characteristics
Central wavelength Bandwidth SNR or NEΔT @ specified input IFOV at s.s.p.
380 nm 10 nm 250 @ 60 W m-2 sr-1 µm-1 250 m
412 nm 10 nm 400 @ 75 W m-2 sr-1 µm-1 250 m
443 nm 10 nm 300 @ 64 W m-2 sr-1 µm-1 250 m
490 nm 10 nm 400 @ 53 W m-2 sr-1 µm-1 250 m
530 nm 20 nm 250 @ 41 W m-2 sr-1 µm-1 250 m
565 nm 20 nm 400 @ 33 W m-2 sr-1 µm-1 250 m
673.5 nm 20 nm 400 @ 23 W m-2 sr-1 µm-1 250 m
673.5 nm 20 nm 250 @ 25 W m-2 sr-1 µm-1 250 m
763 nm 12 nm 1200 @ 40 W m-2 sr-1 µm-1 (@ 1 km) 250 m
868.5 nm 20 nm 400 @ 8 W m-2 sr-1 µm-1 250 m
868.5 nm 20 nm 200 @ 30 W m-2 sr-1 µm-1 250 m
673.5 nm   3 pol 20 nm 250 @ 25 W m-2 sr-1 µm-1 1000 m
868.5 nm   3 pol 20 nm 250 @ 30 W m-2 sr-1 µm-1 1000 m
1050 nm 20 nm 500 @ 57 W m-2 sr-1 µm-1 1000 m
1380 nm 20 nm 150 @ 8 W m-2 sr-1 µm-1 1000 m
1630 nm 200 nm 57 @ 3 W m-2 sr-1 µm-1 250 m
2210 nm 50 nm 211 @ 1.9 W m-2 sr-1 µm-1 1000 m
10.8 µm 0.7 µm 0.2 K @ 300 K 500 m
12.0 µm 0.7 µm 0.2 K @ 300 K 500 m
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
  • Cloud cover
  • Cloud optical depth
  • Cloud top height
  • Cloud top temperature
  • Cloud 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 burden3 - highCloud sensitive.. Daylight only.VIS (with narrow bandwidth), NIR and SWIR channels including 760 nm for high-level aerosol
Aerosol effective radius5 - marginalCloud sensitive.. Daylight only.VIS (with narrow bandwidth), NIR (including 760 nm for high-level aerosol), and SWIR channels
Aerosol mass mixing ratio4 - fairCloud sensitive.. Daylight only.VIS (with narrow bandwidth), NIR and SWIR channels including 760 nm for high-level aerosol
Aerosol Optical Depth3 - highCloud sensitive.. Daylight only.VIS (with narrow bandwidth), NIR and SWIR channels including 760 nm for high-level aerosol
Aerosol type4 - fairCloud sensitive.. Daylight only.VIS (with narrow bandwidth), NIR and SWIR channels including 760 nm for high-level aerosol
Biomass4 - fairCloud sensitive.. Index only.. Daylight only.VIS, NIR and SWIR channels. Biomass inferred from NDVI and LAI
Cloud cover4 - fairNo specific limitation.VIS, NIR and TIR channels
Cloud optical depth3 - highLow-density cloud only.. Daylight only.VIS, NIR and SWIR channels
Cloud top height3 - highNo specific limitation.TIR window channels to estimate cloud top height from its temperature
Cloud top temperature3 - highNo specific limitation.TIR window channels
Cloud type3 - highNo specific limitation.VIS, NIR, SWIR and TIR channels
Colour Dissolved Organic Matter (CDOM)2 - very highCloud sensitive.. Daylight only.Many VIS channels, including narrow and very narrow ones. Suitable for more water types, mainly in open ocean
Downward short-wave irradiance at Earth surface4 - fairCloud sensitive.. Highly indirect.VIS, NIR and SWIR channels
Earth surface albedo4 - fairCloud sensitive.VIS channels
Fire fractional cover4 - fairCloud sensitive.. Coarse spatial resolution.VIS and TIR channels
Fire radiative power5 - marginalCloud sensitive.. Coarse spatial resolution.TIR channels
Fire temperature5 - marginalCloud sensitive.. Coarse spatial resolution.TIR channels
Fraction of Absorbed PAR (FAPAR)2 - very highCloud sensitive.VIS channels including Red at 700 nm
Land surface temperature5 - marginalCloud sensitive.TIR split window channels around 11 micrometers for water vapour correction
Leaf Area Index (LAI)2 - very highCloud sensitive.. Daylight only.VIS, NIR and SWIR channels
Normalised Difference Vegetation Index (NDVI)2 - very highCloud sensitive.VIS and NIR channels
Ocean chlorophyll concentration 2 - very highCloud sensitive.. Daylight only.Many VIS channels, including narrow and very narrow ones. Suitable for more water types, mainly in open ocean
Ocean Diffuse Attenuation Coefficient (DAC)2 - very highCloud sensitive.. Daylight only.Many VIS channels, including narrow and very narrow ones. Suitable for more water types, mainly in open ocean
Ocean suspended sediments concentration2 - very highCloud sensitive.. Daylight only.Many VIS channels, including narrow and very narrow ones. Suitable for more water types, mainly in open ocean
Oil spill cover3 - highCloud sensitive.. Daylight only.VIS channels with narrow bandwidth
Photosynthetically Active Radiation (PAR)3 - highCloud sensitive.VIS channels, range accurately sampled
Sea surface temperature4 - fairCloud sensitive.TIR split window channels around 11 micrometers for water vapour correction
Sea-ice cover2 - very highCloud sensitive.VIS, NIR (for contour enhancement), SWIR (for discrimination from clouds) and TIR channels
Short-wave cloud reflectance4 - fairNo specific limitation.VIS and NIR channels
Snow cover3 - highCloud sensitive.. Daylight only.VIS, NIR and SWIR channels, enabling screening snow from clouds
Soil moisture at surface4 - fairCloud sensitive.. Index only.VIS, NIR, SWIR and TIR channels. Soil moisture inferred from differential brightness and thermal inertia
Integrated Water Vapour (IWV)4 - fairCloud sensitive.. Low troposphere dominant.TIR channels in the 11 micrometers split window
Upward short-wave irradiance at TOA4 - fairSpectral interpolation needed.. Information on BRDF needed.VIS, NIR and SWIR channels
Aerosol volcanic ash4 - fairCloud sensitive.. Daylight only.VIS, NIR and SWIR channels including 760 nm for high-level ashes
Aerosol volcanic ash (Total column)3 - highCloud sensitive.. Daylight only.VIS, NIR and SWIR channels including 760 nm for high-level ashes
Wind (horizontal)5 - marginalCloud or water vapour tracers needed.. Polar regions only.TIR channel(s) around 11 micrometers window