BackForwardInstrument:  GIIRS 

Instrument details
Acronym GIIRS
Full name Geostationary Interferometric Infrared Sounder
Purpose Temperature/humidity sounding and wind profile derivation by tracking water vapour features
Short description MWIR/TIR interferometer with large detector arrays for simultaneous sounding of more pixels. 913 channels on the first flight unit, 1188 on follow-on flight units. Supporting VIS channels for cloud detection [see detailed characteristics below]
Background New development
Scanning Technique Mechanical, bi-axial, 3-axis stabilised satellite, step-and-dwell of a detector matrix. Two operating modes: China area (5000 km x 5000 km) and mesoscale area (1000 km x 1000 km)
Resolution Prototype flight 16 km, follow-on 8 km, at s.s.p.. Supporting VIS: 2 km at s.s.p.
Coverage / Cycle China area (5000 km x 5000 km) in 67 min.  Mesoscale area (1000 km x 1000 km) in 35 min
Mass Power Data Rate

 

Providing Agency CMA
Instrument Maturity Demonstrated by simulations
Utilization Period: 2018-05-05 to ≥2040
Last update: 2016-06-17
Detailed characteristics

Spectral range (µm)

Spectral range (cm-1)

Spectral resolution

NEΔR or SNR

14.3-8.85 µm

700-1130 cm-1

0.8 cm-1 (later: 0.625 cm-1)

0.5 mW m-2 sr-1 cm (later: 0.3 mW m-2 sr-1 cm)

6.06-4.44 µm

1650-2250 cm-1

1.6 cm-1 (later: 1.2 cm-1)

0.1 mW m-2 sr-1 cm (later: 0.06 mW m-2 sr-1 cm)

0.55-0.75 µm

N/A

N/A

200 @ 100 % albedo

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. Frequent sampling (GEO) enables monitoring instability onset
C2H23 - highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. C2H2 lines around 7.5 and 13.7 micrometers. Frequent sampling (GEO) enables monitoring diurnal variations
C2H63 - highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. C2H6 lines around 12 micrometers. Frequent sampling (GEO) enables monitoring diurnal variations
CFC-113 - highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. CFC-11 lines around 9.2 and 11.7 micrometers. Frequent sampling (GEO) enables monitoring diurnal variations
CFC-123 - highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. CFC-12 lines around 8.8 and 10.8 micrometers. Frequent sampling (GEO) enables monitoring diurnal variations
ClONO23 - highCloud sensitive.. Coarse vertical resolution.MWIR and TIR spectrometry. ClONO2 lines around 5.7, 7.7 and 12.5 micrometers. Frequent sampling (GEO) enables monitoring diurnal variations
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
CO23 - highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. CO2 lines around 15 micrometers. Frequent sampling (GEO) enables monitoring diurnal variations
COS3 - highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. COS lines around 11.6 micrometers. Frequent sampling (GEO) enables monitoring diurnal variations
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. Frequent sampling (GEO) enables monitoring diurnal variations
Height of the top of PBL4 - fairCloud sensitive.MWIR and TIR spectrometry. Height of PBL top from temperature profile. Frequent sampling (GEO) enables monitoring the PBL evolution
Height of the tropopause4 - fairCloud sensitive.TIR spectrometry. Height of tropopause from temperature profile. Frequent sampling (GEO) enables monitoring the tropopause evolution
HNO33 - highCloud sensitive.. Coarse vertical resolution.MWIR and TIR spectrometry. HNO3 lines around 5.9, 7.6 and 11.3 micrometers. Frequent sampling (GEO) enables monitoring diurnal variations
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 column)5 - marginalCloud sensitive.TIR spectrometry. NO2 lines around 6.1 micrometers. Frequent sampling (GEO) enables monitoring diurnal variations
O33 - highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. Ozone band around 9.7 micrometers. Frequent sampling (GEO) enables monitoring diurnal variations
O3 (Total column)3 - highCloud sensitive.TIR channel(s). Ozone lines in band around 9.7 micrometers. Frequent sampling (GEO) enables monitoring diurnal variations
PAN3 - highCloud sensitive.. Coarse spatial resolution.MWIR and TIR spectrometry. PAN lines around 5.7, 8.6 and 12.5 micrometers. Frequent sampling (GEO) enables monitoring diurnal variations
PSC occurrence2 - very highMarginal view from GEO.. Coarse 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. Frequent sampling (GEO) for diurnal variations
SO23 - highCloud sensitive.. Coarse vertical resolution.TIR spectrometry. SO2 lines around 7.3 and 8.6 micrometers. Frequent sampling (GEO) for sources monitoring
SO2 (Total column)4 - fairCloud sensitive.TIR spectrometry. SO2 lines around 7.3 and 8.6 micrometers. Frequent sampling (GEO) for sources monitoring
Specific humidity1 - primaryCloud sensitive.TIR spectrometry in the water vapour band around 6.3 micrometers. Frequent sampling (GEO) enables monitoring instability onset
Integrated Water Vapour (IWV)2 - very highCloud sensitive.TIR spectrometry in the bands around 6.3 and above 11 micrometers. Frequent sampling (GEO) enables monitoring instability onset
Temperature of the tropopause3 - highCloud sensitive.TIR spectrometry. Tropopause temperature from temperature profile. Frequent sampling (GEO) enables monitoring the tropopause evolution
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)2 - very highCloud sensitive.. Water vapour tracers needed.TIR spectrometry in the 6.3 micrometers band. Wind profile in clear air by tracking water vapour patches in the humidity profile