BackForwardInstrument:  AVHRR 

Instrument details
Acronym AVHRR
Full name Advanced Very High Resolution Radiometer
Purpose Multi-purpose imagery
Short description 4-channel radiometer covering VIS, NIR, MWIR and TIR, respectively [see detailed characteristics below]
Background Digitised version of VHRR (Very High Resolution Radiometer) previously flown on NOAA 2 to 5; 4 channels instead of 2
Scanning Technique Cross-track: 2048 pixel of 800 m s.s.p., swath 2900 km - Along-track: six 1.1-km lines/s
Resolution 1.1 km IFOV s.s.p.
Coverage / Cycle Global coverage twice/day (IR) or once/day (VIS)
Mass 33 kg Power 27 W Data Rate 621.3 kbps

 

Providing Agency NOAA
Instrument Maturity Flown on operational programme
Utilization Period: 1979 to 2001
Last update: 2017-03-26
Detailed characteristics
Central wavelength Spectral interval SNR or NEΔT @ specified input
0.615 µm 0.55 - 0.68 µm 9 @ 0.5 % albedo
0.912 µm 0.725 - 1.10 µm 9 @ 0.5 % albedo
3.74 µm 3.55 - 3.93 µm 0.12 K @ 300 K
11.0 µm 10.5 - 11.5 µm 0.12 K @ 300 K
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
WIGOS Subcomponents
  • Subcomponent 1
  • VIS/IR imagery; realisation of a Day/Night band [in SSO]
  • VIS/IR imager [in SSO]
Mission objectives
Primary mission objectives
  • Cloud cover
  • Cloud optical depth
  • Cloud top temperature
  • Cloud type
  • Normalised Difference Vegetation Index (NDVI)
  • Sea surface temperature
  • Sea-ice cover
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
Note: * Primary mission objective.
VariableRelevance for measuring this variableOperational limitationsExplanation
Biomass5 - marginalCloud sensitive.. Index only.. Daylight only.VIS and NIR channels. Biomass inferred from NDVI
Cloud cover*2 - very highNo specific limitation.VIS, NIR, MWIR and TIR channels
Cloud drop effective radius3 - highAt cloud top.. Daylight only.VIS, NIR and MWIR channels (for differentiation)
Cloud ice effective radius3 - highAt cloud top.. Daylight only.VIS, NIR and MWIR channels (for differentiation)
Cloud optical depth*4 - fairLow-density cloud only.. Daylight only.VIS and NIR channels
Cloud top temperature*5 - marginalNo specific limitation.TIR window channel(s)
Cloud type*2 - very highNo specific limitation.VIS, NIR, MWIR and TIR channels
Downward short-wave irradiance at Earth surface5 - marginalCloud sensitive.. Highly indirect.VIS and NIR channels
Fire fractional cover4 - fairCloud sensitive.. Coarse spatial resolution.VIS, MWIR and TIR channels
Fire radiative power2 - very highCloud sensitive.. Coarse spatial resolution.MWIR and TIR channels
Fire temperature2 - very highCloud sensitive.. Coarse spatial resolution.MWIR and TIR channels
Land surface temperature3 - highCloud sensitive.MWIR and TIR window channels (high sensitivity to high temperature, cloud impact reduction, water vapour correction)
Leaf Area Index (LAI)4 - fairCloud sensitive.. Daylight only.VIS and NIR channels. LAI inferred from NDVI
Normalised Difference Vegetation Index (NDVI)*3 - highCloud sensitive.VIS and NIR channels
Sea surface temperature*4 - fairCloud sensitive.. Affected by sunlight.MWIR window channel(s) around 3.7 micrometers (cloud impact reduction)
Short-wave cloud reflectance5 - marginalNo specific limitation.VIS and NIR channels
Snow cover4 - fairCloud sensitive.. Daylight only.VIS and NIR channels
Soil moisture at surface4 - fairCloud sensitive.. Index only.VIS, NIR, MWIR and TIR channels. Soil moisture inferred from differential brightness and thermal inertia
Upward short-wave irradiance at TOA5 - marginalSpectral interpolation needed.. Information on BRDF needed.VIS and NIR channels
Aerosol volcanic ash5 - marginalCloud sensitive.. Daylight only.VIS and NIR channels
Aerosol volcanic ash Total Column5 - marginalCloud sensitive.. Daylight only.VIS and NIR channels
Wind (horizontal)5 - marginalLimited to high latitudes.. Cloud or water vapour tracers needed.TIR channel(s) around 11 micrometers window
Sea-ice cover*3 - highCloud sensitive.VIS, NIR (for contour enhancement), MWIR and TIR channels