BackForwardInstrument:  IASI 

Instrument details
Acronym IASI
Full name Infrared Atmospheric Sounding Interferometer
Purpose Temperature/humidity sounding, ozone profile, and total-column reactive trace gases and greenhouse gases
Short description Interferometer with 8461 channels, with one embedded IR imaging channel
Background New development
Scanning Technique Cross-track: 30 steps of 48 km ssp, swath 2130 km - Along-track: one 48-km line every 8 s
Resolution 4 x 12-km IFOV close to the centre of a 48 x 48 km2 cell (average sampling distance: 24 km)
Coverage / Cycle Near-global coverage twice/day
Mass 236 kg Power 210 W Data Rate 1.5 Mbps (after onboard processing)

 

Providing Agency CNES
Instrument Maturity Flown on operational programme
Utilization Period: 2007-05-15 to ≥2024
Last update: 2012-09-04
Detailed characteristics
Spectral range (µm) Spectral range (cm-1) Spectral resolution (unapodised) NEΔT @ specified scene temperature
8.26 - 15.50 µm 645 - 1210 cm-1 0.25 cm-1 0.2-0.3 K @ 280 K
5.00 - 8.26 µm 1210 - 2000 cm-1 0.25 cm-1 0.2-0.5 K @ 280 K
3.62 - 5.00 µm 2000 - 2760 cm-1 0.25 cm-1 0.5-2.0 K @ 280 K
10.3-12.5 µm N/A N/A 0.8 K @ 280 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
Mission objectives
Primary mission objectives
  • Atmospheric temperature
  • Height of the top of PBL
  • Height of the tropopause
  • Integrated Water Vapour (IWV)
  • Specific humidity
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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
Atmospheric temperature1 - primaryCloud sensitive.MWIR and TIR spectrometry in the CO2 4.3 and 15 micrometer bands
C2H23 - highCloud sensitive.TIR spectrometry. C2H2 lines around 7.5 and 13.7 micrometers
C2H64 - fairCloud sensitive.TIR spectrometry. C2H6 lines around 12 micrometers
CFC-114 - fairCloud sensitive.. Coarse vertical resolution.TIR spectrometry. CFC-11 lines around 9.2 and 11.7 micrometers
CFC-124 - fairCloud sensitive.TIR spectrometry. CFC-12 lines around 8.8 and 10.8 micrometers
CH44 - fairCloud sensitive.. Coarse vertical resolution.MWIR and TIR spectrometry. CH4 lines around 4.3 and 7.7 micrometers
ClONO24 - fairCloud sensitive.MWIR and TIR spectrometry. ClONO2 lines around 5.7, 7.7 and 12.5 micrometers
Cloud cover2 - very highDiscontinuous coverage.MWIR and TIR spectrometry
Cloud top height1 - primaryDiscontinuous 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 type3 - highDiscontinuous coverage.MWIR and TIR spectrometry
CO4 - fairCloud sensitive.. Coarse vertical resolution.MWIR spectrometry. CO lines around 4.6 micrometers
CO24 - fairCloud sensitive.. Coarse vertical resolution.MWIR and TIR spectrometry. CO2 lines around 4.3 and 15 micrometers
COS3 - highCloud sensitive.. Coarse vertical resolution.MWIR and TIR spectrometry. COS lines around 4.8 and 11.6 micrometers
Downward long-wave irradiance at Earth surface4 - fairCloud sensitive.. Highly indirect.MWIR and TIR spectrometry including water vapour and CO2 bands
H2O2 - very highCloud sensitive.MWIR/TIR spectrometry in a range centred on 6.3 micrometers
Height of the top of PBL3 - highCloud sensitive.MWIR and TIR spectrometry. Height of PBL top from temperature profile
Height of the tropopause3 - highCloud sensitive.TIR spectrometry. Height of tropopause from temperature profile
HNO34 - fairCloud 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 emissivity3 - highCloud sensitive.. Long time series needed.MWIR and TIR spectrometry measuring land temperature in many windows. Emissivity inferred by statistical analysis
N2O4 - fairCloud sensitive.. Coarse vertical resolution.TIR spectrometry. N2O lines around 7.7 micrometers
N2O54 - fairCloud sensitive.. Coarse vertical resolution.MWIR and TIR spectrometry. N2O5 lines around 5.8 and 8 micrometers
NO4 - fairCloud sensitive.. Coarse vertical resolution.MWIR spectrometry. NO lines around 5.3 micrometers
NO24 - fairCloud sensitive.. Coarse vertical resolution.TIR spectrometry. NO2 lines around 6.1 micrometers
NO2 (Total column)3 - highCloud sensitive.TIR spectrometry. NO2 lines around 6.1 micrometers
O33 - highCloud sensitive.TIR spectrometry. Ozone band around 9.7 micrometers
O3 (Total column)2 - very highCloud sensitive.TIR channel(s). Ozone lines in band around 9.7 micrometers
PAN3 - highCloud sensitive.MWIR and TIR spectrometry. PAN lines around 5.7, 8.6 and 12.5 micrometers
PSC occurrence4 - fairCoarse 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)
SF64 - fairCloud sensitive.. Coarse vertical resolution.TIR spectrometry. SF6 lines around 10.5 micrometers
SO23 - highCloud sensitive.TIR spectrometry. SO2 lines around 7.3 and 8.6 micrometers
SO2 (Total column)2 - very highCloud sensitive.TIR spectrometry. SO2 lines around 7.3 and 8.6 micrometers
Specific humidity2 - very highCloud 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 tropopause2 - very highCloud 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 TOA2 - very 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 surface3 - highCloud 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