BackForwardInstrument:  THIR 

Instrument details
Acronym THIR
Full name Temperature-Humidity Infrared Radiometer
Purpose Cloud observation
Short description Two-channel IR radiometer, 6.5-7.0 ?m and 10.5-12.5 ?m. Direct read-out on Nimbus-4
Background Prototype of multichannel IR radiometers
Scanning Technique Cross-track, 48 rpm (8.1 km/line), swath horizon-to-horizon
Resolution 7 km at s.s.p. (window channel) and 22 km at s.s.p. (water vapour channel)
Coverage / Cycle Global, twice/day
Mass 9 kg Power 8.5 W Data Rate Analogue: 0.8 kHz base band

 

Providing Agency NASA
Instrument Maturity Flown on an R&D satellite
Utilization Period: 1970 to 1994-08-01
Last update: 2013-11-19
Detailed characteristics
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
  • Integrated Water Vapour (IWV)
Secondary mission objectives
  • Sea surface temperature
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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 cover5 - marginalNo specific limitation.TIR channel(s)
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)
Fire fractional cover5 - marginalCloud sensitive.. Coarse spatial resolution.TIR channels
Fire radiative power5 - marginalCloud sensitive.. Coarse spatial resolution.TIR channels
Fire temperature5 - marginalCloud sensitive.. Coarse spatial resolution.TIR channels
Sea surface temperature5 - marginalCloud sensitive.TIR window channel(s) around 11 micrometers .
Integrated Water Vapour (IWV)4 - fairCloud sensitive.. Middle troposphere dominant.TIR channels in the water vapour band around 6.3 micrometers
Wind (horizontal)4 - fairLimited to high latitudes.. Cloud or water vapour tracers needed.TIR channels in the 11 micrometers window and the 6.3 micrometers water vapour band