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: 2017-09-24 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
C2H24 - fairCloud sensitive.. Coarse vertical resolution.TIR spectrometry. C2H2 lines around 7.5 and 13.7 micrometers. Frequent sampling (GEO) enables monitoring diurnal variations
C2H65 - marginalCloud sensitive.. Coarse vertical resolution.TIR spectrometry. C2H6 lines around 12 micrometers. Frequent sampling (GEO) enables monitoring diurnal variations
CFC-114 - fairCloud sensitive.. Coarse vertical resolution.TIR spectrometry. CFC-11 lines around 9.2 and 11.7 micrometers. Frequent sampling (GEO) enables monitoring diurnal variations
CFC-124 - fairCloud sensitive.. Coarse vertical resolution.TIR spectrometry. CFC-12 lines around 8.8 and 10.8 micrometers. Frequent sampling (GEO) enables monitoring diurnal variations
ClONO24 - fairCloud 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 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
CO25 - marginalCloud sensitive.. Coarse vertical resolution.TIR spectrometry. CO2 lines around 15 micrometers. Frequent sampling (GEO) enables monitoring diurnal variations
COS4 - fairCloud 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 surface4 - fairCloud sensitive.. Highly indirect.MWIR and TIR spectrometry including water vapour and CO2 bands
H2O4 - fairCloud 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
HNO34 - fairCloud 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 emissivity3 - highCloud sensitive.. Long time series needed.MWIR and TIR spectrometry measuring land temperature in many windows. Emissivity inferred by statistical analysis
NO2 (Total column)4 - fairCloud 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
PAN4 - fairCloud 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 occurrence5 - marginalMarginal 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)
SF64 - fairCloud sensitive.. Coarse vertical resolution.TIR spectrometry. SF6 lines around 10.5 micrometers. Frequent sampling (GEO) for diurnal variations
SO24 - fairCloud 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)1 - primaryCloud 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 TOA3 - 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
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