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: 2018-03-06
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
C2H22 - very highCloud sensitive.TIR spectrometry. C2H2 lines around 7.5 and 13.7 micrometers
C2H62 - very highCloud sensitive.TIR spectrometry. C2H6 lines around 12 micrometers
CFC-112 - very highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. CFC-11 lines around 9.2 and 11.7 micrometers
CFC-122 - very highCloud sensitive.TIR spectrometry. CFC-12 lines around 8.8 and 10.8 micrometers
CH42 - very highCloud sensitive.. Coarse vertical resolution.MWIR and TIR spectrometry. CH4 lines around 4.3 and 7.7 micrometers
ClONO21 - primaryCloud sensitive.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
CO3 - highCloud sensitive.. Coarse vertical resolution.MWIR spectrometry. CO lines around 4.6 micrometers
CO22 - very highCloud sensitive.. Coarse vertical resolution.MWIR and TIR spectrometry. CO2 lines around 4.3 and 15 micrometers
COS2 - very highCloud sensitive.. Coarse vertical resolution.MWIR and TIR spectrometry. COS lines around 4.8 and 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.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
HNO32 - very 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
N2O3 - highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. N2O lines around 7.7 micrometers
N2O52 - very highCloud sensitive.. Coarse vertical resolution.MWIR and TIR spectrometry. N2O5 lines around 5.8 and 8 micrometers
NO2 - very highCloud sensitive.. Coarse vertical resolution.MWIR spectrometry. NO lines around 5.3 micrometers
NO23 - highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. NO2 lines around 6.1 micrometers
NO2 (Total column)2 - very highCloud sensitive.TIR spectrometry. NO2 lines around 6.1 micrometers
O33 - highCloud sensitive.TIR spectrometry. Ozone band around 9.7 micrometers
O3 (Total column)3 - highCloud sensitive.TIR channel(s). Ozone lines in band around 9.7 micrometers
PAN2 - very highCloud sensitive.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)
SF62 - very highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. SF6 lines around 10.5 micrometers
SO21 - primaryCloud sensitive.TIR spectrometry. SO2 lines around 7.3 and 8.6 micrometers
SO2 (Total column)1 - primaryCloud sensitive.TIR spectrometry. SO2 lines around 7.3 and 8.6 micrometers
Specific humidity1 - 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 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 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 - highCloud sensitive.. Limited to high latitudes.TIR spectrometry in the 6.3 micrometers band. Wind profile in clear air by tracking water vapour patches in the humidity profile