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Instrument: 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 1980-09-30
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
WIGOS Subcomponents
No WIGOS subcomponents have been defined.
Mission objectives
Primary mission objectives Cloud cover Cloud top height Cloud top temperature Integrated Water Vapour (IWV)
Secondary mission objectives
Opportunity objectives Fire fractional cover Fire radiative power Fire temperature Wind (horizontal) Show all Show fewer
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
Variable Relevance for measuring this variable Operational limitations Explanation
Cloud cover 5 - marginal No specific limitation. TIR channel(s)
Cloud top height 3 - high No specific limitation. TIR channels in window and water vapour band (for emissivity) to estimate cloud top height from its temperature
Cloud top temperature 3 - high No specific limitation. TIR channels in window and water vapour band (for emissivity)
Fire fractional cover 5 - marginal Cloud sensitive.. Coarse spatial resolution. TIR channels
Fire radiative power 5 - marginal Cloud sensitive.. Coarse spatial resolution. TIR channels
Fire temperature 5 - marginal Cloud sensitive.. Coarse spatial resolution. TIR channels
Sea surface temperature 5 - marginal Cloud sensitive. TIR window channel(s) around 11 micrometers .
Integrated Water Vapour (IWV) 4 - fair Cloud sensitive.. Middle troposphere dominant. TIR channels in the water vapour band around 6.3 micrometers
Wind (horizontal) 4 - fair Limited to high latitudes.. Cloud or water vapour tracers needed. TIR channels in the 11 micrometers window and the 6.3 micrometers water vapour band