BackForwardInstrument:  ALI 

Instrument details
Acronym ALI
Full name Advanced Land Imager
Purpose Advanced technology for high-resolution land and vegetation observation
Short description 10 VIS/NIR/SWIR channels, including one panchromatic [see detailed characteristics below]
Background Preparing replacement of the ETM+ flown on Landsat-7
Scanning Technique Pushbroom; 1230 pixel/line (9 narrow-band channels), 3700 pixel/line (PAN); swath 37 km [reduced configuration for demonstration purpose - there should be 5 such arrays, to cover a 185 km swath]
Resolution 30 m (9 narrow-band channels), 10 m (PAN)
Coverage / Cycle Global coverage in 80 days, in daylight [for full configuration it would be 16 days]
Mass 106 kg Power 100 W Data Rate 300 Mbps

 

Providing Agency NASA
Instrument Maturity Flown on an R&D satellite
Utilization Period: 2001 to ≥2017
Last update: 2017-03-27
Detailed characteristics
Central wavelength Spectral interval SNR @ specified input spectral radiance
443 nm 433 - 453 nm 339 @ 14.8 mW cm-2 sr-1 µm-1
482 nm 450 - 515 nm 572 @ 17.1 mW cm-2 sr-1 µm-1
565 nm 525 - 605 nm 1001 @ 16.1 mW cm-2 sr-1 µm-1
660 nm 630 - 690 nm 1039 @ 13.4 mW cm-2 sr-1 µm-1
790 nm 775 - 805 nm 722 @ 10.4 mW cm-2 sr-1 µm-1
867 nm 845 - 890 nm 710 @ 8.73 mW cm-2 sr-1 µm-1
1250 nm 1200 - 1300 nm 662 @ 4.42 mW cm-2 sr-1 µm-1
1650 nm 1550 - 1750 nm 1040 @ 2.15 mW cm-2 sr-1 µm-1
2215 nm 2080 - 2350 nm 912 @ 0.68 mW cm-2 sr-1 µm-1
Panchromatic 480 - 690 nm 348 @ 15.0 mW cm-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 Absorbed PAR (FAPAR)
  • Fraction of vegetated land
  • Land cover
  • Leaf Area Index (LAI)
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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 depth4 - fairLow-density cloud only.. Infrequent coverage.. Daylight only.VIS, NIR and SWIR channels
Earth surface albedo4 - fairCloud sensitive.. Infrequent coverage.VIS channels
Fire fractional cover1 - primaryCloud sensitive.. Infrequent coverage.. Daylight only.Panchromatic channel with high resolution, for fire boundary detection
Fraction of Absorbed PAR (FAPAR)3 - highCloud sensitive.. Infrequent coverage.VIS channels including Red at 700 nm
Fraction of vegetated land2 - very highCloud sensitive.. Daylight only.VIS, NIR and SWIR channels
Glacier cover2 - very highCloud sensitive.. Long time for mapping.. Daylight only.VIS, NIR, SWIR and panchromatic channels for accurate boundary detection and screening ice from clouds
Land cover3 - highCloud sensitive.. Daylight only.VIS, NIR and SWIR channels
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)4 - fairCloud 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 reflectance5 - marginalInfrequent coverage.VIS, NIR and SWIR channels. Unsuitable dynamic range (saturation)
Snow cover2 - very highCloud sensitive.. Infrequent coverage.. Daylight only.VIS, NIR, SWIR (snow/cloud discrimination) and panchromatic (higher resolution) channels
Soil moisture at surface5 - marginalCloud sensitive.. Index only.. Infrequent coverage.. Daylight only.VIS, NIR and SWIR channels. Soil moisture inferred from differential brightness
Soil type4 - fairCloud 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 type3 - 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 column)5 - marginalCloud sensitive.. Infrequent coverage.. Daylight only.VIS, NIR and SWIR channels