BackForwardInstrument:  IMAGER (GOES 8-11) 

Instrument details
Acronym IMAGER (GOES 8-11)
Full name GOES Imager
Purpose Multi-purpose imagery and wind derivation by tracking clouds and water vapour features
Short description 5 channels covering VIS, MWIR and TIR [see detailed characteristics below]
Background Replacing VAS flown on GOES 4 to 7, separating the imagery from the sounding function.
Scanning Technique Mechanical, 3-axis stabilised satellite, E-W continuous, S-N stepping
Resolution 4.0 km for IR channels; 1.0 km for the VIS channel
Coverage / Cycle Full disk every 30 min.  Limited areas in correspondingly shorter time intervals
Mass 140 kg Power 130 W Data Rate 2.62 Mbps

 

Providing Agency NOAA
Instrument Maturity Flown on operational programme
Utilization Period: 1994-11-01 to 2011-12-05
Last update: 2016-10-16
Detailed characteristics
Central wavelength Spectral interval SNR or NEΔT @ specified input
0.65 µm 0.55 - 0.75 µm 250 @ 100 % albedo
3.90 µm 3.80 - 4.00 µm 0.11 K @ 300 K
6.75 µm 6.50 - 7.00 µm 0.14 K @ 300 K
10.70 µm 10.2 - 11.2 µm 0.09 K @ 300 K
11.95 µm 11.5 - 12.4 µm 0.70 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
Mission objectives
Primary mission objectives
  • Cloud cover
  • Cloud top height
  • Cloud top temperature
  • Cloud type
  • Integrated Water Vapour (IWV)
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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
Accumulated precipitation (over 24 h)3 - highConvective precipitation dominant.. Calibration by MW needed.TIR channel(s) in the 10-13 micrometers range. Frequent sampling (GEO) is essential for accumulated precipitation
Cloud cover3 - highNo specific limitation.VIS, MWIR and TIR channels
Cloud top height3 - highNo specific limitation.TIR channels in window and water vapour band (for emissivity) to estimate cloud top height from its temperature
Cloud top temperature2 - very highNo specific limitation.TIR channels in window and water vapour band (for emissivity)
Cloud type3 - highNo specific limitation.VIS, MWIR and TIR channels
Downward long-wave irradiance at Earth surface5 - marginalCloud sensitive.. Highly indirect.MWIR and TIR channels including the water vapour band
Fire fractional cover2 - very highCloud sensitive.. Coarse spatial resolution.VIS, MWIR and TIR channels. Frequent sampling (GEO) enables early detection
Fire radiative power2 - very highCloud sensitive.. Coarse spatial resolution.MWIR and TIR channels. Frequent sampling (GEO) enables early detection
Fire temperature2 - very highCloud sensitive.. Coarse spatial resolution.MWIR and TIR channels. Frequent sampling (GEO) enables early detection
Land surface temperature4 - fairCloud sensitive.MWIR and TIR window channels (high sensitivity to high temperature, cloud impact reduction, water vapour correction)
Precipitation intensity at surface (liquid or solid)5 - marginalConvective precipitation dominant.. Calibration by MW needed.TIR channel(s) in the 11 micrometers window. Frequent sampling (GEO) consistent with precipitation temporal variability
Sea surface temperature2 - very highCloud sensitive.MWIR and TIR window channels around 3.7 and 11 micrometers (cloud impact reduction, water vapour correction)
Snow cover4 - fairCloud sensitive.. Daylight only.VIS channel(s). Frequent sampling (GEO) improves probability of cloud-free views
Soil moisture at surface3 - highCloud sensitive.. Index only.VIS, MWIR and TIR channels. Soil moisture inferred from thermal inertia, that is accurately measured by frequent sampling (GEO)
Integrated Water Vapour (IWV)2 - very highCloud sensitive.TIR channels around 6.3 micrometers and in the 11 micrometers split window
Upward long-wave irradiance at TOA5 - marginalSpectral interpolation needed.MWIR and TIR channels in windows around 3.7 and 11 micrometers, and in the water vapour band around 6.3 micrometers
Upward long-wave irradiance at Earth surface5 - marginalCloud sensitive.. Highly indirect.MWIR and TIR channels in windows around 3.7 and 11 micrometers, and in the water vapour band around 6.3 micrometers
Aerosol volcanic ash (Total column)2 - very highCloud sensitive.TIR channel(s). Frequent sampling (GEO) enables early detection of ash plumes
Wind (horizontal)3 - highCloud or water vapour tracers needed.VIS channel(s) and TIR channels around 6.3 and 11 micrometers. Frequent sampling (GEO) enables inference from cloud or water vapour pathces motion