BackForwardInstrument:  VHRR (INSAT) 

Instrument details
Acronym VHRR (INSAT)
Full name Very High Resolution Radiometer
Purpose Multi-purpose imagery and wind derivation by tracking clouds and water vapour features
Short description 3 VIS/TIR channels [see detailed characteristics below]
Background Heritage of VHRR flown on ATS-6
Scanning Technique Mechanical, 3-axis stabilised satellite, E-W continuous, S-N stepping
Resolution 8.0 km for IR channels; 2 km for the VIS channel
Coverage / Cycle Full disk every 3 hours for INSAT-2E, 1 hour for INSAT-3A (with half-hourly triplets around 00 and 12 UT for winds), half-hour for Kalpana-1
Mass 60 kg Power 37 W Data Rate 530 kbps

 

Providing Agency ISRO
Instrument Maturity Flown on operational programme
Utilization Period: 1982 to 1982-09-06
Last update: 2017-03-27
Detailed characteristics
Central wavelength Spectral interval SNR or NEΔT @ specified input
0.65 µm 0.55 - 0.75 µm 6 @ 2.5 % albedo
6.40 µm 5.70 - 7.10 µm 0.5 K @ 300 K
11.5 µm 10.5 - 12.5 µm 0.25 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 No WIGOS subcomponents have been defined.
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
Cloud cover4 - fairNo specific limitation.VIS 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 temperature3 - highNo specific limitation.TIR channels in window and water vapour band (for emissivity)
Cloud type4 - fairDaylight only.VIS and TIR channels
Fire fractional cover4 - fairCloud sensitive.. Coarse spatial resolution.VIS and TIR channels
Fire radiative power5 - marginalCloud sensitive.. Coarse spatial resolution.TIR channels. Frequent sampling (GEO) enables early detection
Fire temperature5 - marginalCloud sensitive.. Coarse spatial resolution.TIR channels. Frequent sampling (GEO) enables early detection
Precipitation intensity at surface (liquid or solid)3 - highConvective precipitation dominant.. Calibration by MW needed.TIR channel(s) in the 11 micrometers window. Frequent sampling (GEO) consistent with precipitation temporal variability
Sea surface temperature5 - marginalCloud sensitive.TIR window channel(s) around 11 micrometers .
Snow cover5 - marginalCloud sensitive.. Daylight only.VIS channel(s). Frequent sampling (GEO) improves probability of cloud-free views
Soil moisture at surface4 - fairCloud sensitive.. Index only.VIS and TIR window channels. Soil moisture inferred from thermal inertia, that is accurately measured by frequent sampling (GEO)
Integrated Water Vapour (IWV)4 - fairCloud sensitive.. Middle troposphere dominant.TIR channels in the water vapour band around 6.3 micrometers
Aerosol volcanic ash Total Column1 - primaryCloud 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
Accumulated precipitation (over 24 h)4 - fairConvective precipitation dominant.. Calibration by MW needed.TIR channel(s) in the 10-13 micrometers range. Frequent sampling (GEO) is essential for accumulated precipitation.