BackForwardInstrument:  HIRAS 

Instrument details
Acronym HIRAS
Full name Hyperspectral Infrared Atmospheric Sounder
Purpose Temperature/humidity sounding, ozone profile and total-column green-house gases
Short description
  • Michelson interferometer with three bands, 1370 channels [see detailed characteristics below]
  • Calibration monitoring here
Background

Replacing IRAS on FY 3A, 3B and 3C
Scanning Technique

29 fields of regard/scan line, with 2 x 2 pixel arrays giving 29 x 4 pixels per scan line; swath 50.4 degrees (2400 km).
Resolution 1.1 degree (16 km at nadir) IFOV
Coverage / Cycle Near-global, twice/day
Mass 120 kg Power 129 W Data Rate

 

Providing Agency CMA
Instrument Maturity Backed by strong heritage
Utilization Period: 2018 to 2024
Last update: 2024-09-09
Detailed characteristics

Spectral range (µm)

Spectral range (cm-1)

Spectral resolution(unapodised)

NEΔT @ specified scene temperature

8.80-15.39 µm

650-1136 cm-1

0.625 cm-1

0.15-0.4 K @ 250 K

5.71-8.26 µm

1210-1750 cm-1

1.25 cm-1

0.1-0.7 K @ 250 K

3.92-4.64 µm

2155-2550 cm-1

2.5 cm-1

0.3-1.2 K @ 250 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
  • Cross-nadir infrared sounder, possibly including VIS channels
WIGOS Subcomponents
  • Subcomponent 1
  • IR hyperspectral sounders [in SSO]
  • IR hyperspectral sounder [in SSO]
Mission objectives
Primary mission objectives
  • Atmospheric temperature
  • Height of the top of PBL
  • Height of the tropopause
  • Integrated Water Vapour (IWV)
  • Specific humidity
  • Temperature of the tropopause
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
Atmospheric temperature*2 - very highCloud sensitive.MWIR spectrometry in the CO2 4.3 micrometer band; TIR in the CO2 15 micrometer band
C2H23 - highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. C2H2 lines around 7.5 and 13.7 micrometers
C2H63 - highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. C2H6 lines around 12 micrometers
CFC-113 - highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. CFC-11 lines around 9.2 and 11.7 micrometers
CFC-123 - highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. CFC-12 lines around 8.8 and 10.8 micrometers
ClONO23 - highCloud sensitive.. Coarse vertical resolution.MWIR and TIR spectrometry. ClONO2 lines around 5.7, 7.7 and 12.5 micrometers
Cloud cover3 - highDiscontinuous coverage.MWIR and TIR spectrometry
Cloud top height2 - very highDiscontinuous coverage.MWIR and TIR spectrometry in window and water vapour band (for emissivity) to estimate cloud top height from its temperature
Cloud top temperature1 - primaryDiscontinuous coverage.TIR spectrometry in window and water vapour band (for emissivity)
Cloud type4 - fairDiscontinuous coverage.MWIR and TIR spectrometry
CO2 mole fraction3 - highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. CO2 lines around 15 micrometers
COS3 - highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. COS lines around 11.6 micrometers
Downward long-wave irradiance at Earth surface1 - primaryCloud sensitive.. Highly indirect.MWIR and TIR spectrometry including water vapour and CO2 bands
H2O2 - very highCloud sensitive.. Coarse vertical resolution.MWIR/TIR spectrometry in a range centred on 6.3 micrometers
Height of the top of PBL*4 - fairCloud sensitive.MWIR and TIR spectrometry. Height of PBL top from temperature profile
Height of the tropopause*5 - marginalCloud sensitive.TIR spectrometry. Height of tropopause from temperature profile
HNO33 - highCloud sensitive.. Coarse vertical resolution.MWIR and TIR spectrometry. HNO3 lines around 5.9, 7.6 and 11.3 micrometers
Land surface temperature2 - very highCloud sensitive.. Coarse spatial resolution.MWIR and TIR spectrometry (inclusive of several narrow-bandwidth windows and absorption bands for atmospheric corrections)
Long-wave Earth surface emissivity1 - primaryCloud sensitive.. Long time series needed.MWIR and TIR spectrometry measuring land temperature in many windows. Emissivity inferred by statistical analysis
NO2 Total Column5 - marginalAlong-track only.. Cloud sensitive.TIR spectrometry. NO2 lines around 6.1 micrometers
O33 - highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. Ozone band around 9.7 micrometers
O3 Total Column3 - highCloud sensitive.TIR channel(s). Ozone lines in band around 9.7 micrometers
PAN3 - highCloud sensitive.. Coarse spatial resolution.MWIR and TIR spectrometry. PAN lines around 5.7, 8.6 and 12.5 micrometers
PSC occurrence2 - very highCoarse vertical resolution.MWIR and TIR spectroscopy
Sea surface temperature1 - primaryCloud sensitive.MWIR and TIR spectrometry (inclusive of several narrow-bandwidth windows and absorption bands for atmospheric corrections)
SF63 - highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. SF6 lines around 10.5 micrometers
SO23 - highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. SO2 lines around 7.3 and 8.6 micrometers
SO2 Total Column4 - fairCloud sensitive.TIR spectrometry. SO2 lines around 7.3 and 8.6 micrometers
Specific humidity*1 - primaryCloud sensitive.TIR spectrometry in the water vapour band around 6.3 micrometers
Integrated Water Vapour (IWV)*2 - very highCloud sensitive.TIR spectrometry in the bands around 6.3 and above 11 micrometers
Temperature of the tropopause*4 - fairCloud sensitive.TIR spectrometry. Tropopause temperature from temperature profile
Upward spectral radiance at TOA2 - very highMissing all Short-waves.MWIR and TIR spectrometry resolving water vapour lines in the bands around 6.3 micrometers and 11 to 15 micrometers; and other greenhouse gases
Upward long-wave irradiance at TOA3 - highSpectral interpolation needed.MWIR and TIR spectrometry in the windows regions around 3.7 and 11 micrometers, and in water vapour and CO2 bands around 4,3, 6.3 and 15 micrometers
Upward long-wave irradiance at Earth surface1 - primaryCloud sensitive.. Highly indirect.MWIR and TIR channels in windows around 3.7 and 11 micrometers, and in water vapour and CO2 bands around 4,3, 6.3 and 15 micrometers
Wind (horizontal)3 - highLimited to high latitudes.. Cloud sensitive.TIR spectrometry in the 6.3 micrometers band. Wind profile in clear air by tracking water vapour patches in the humidity profile