BackForwardInstrument:  MERSI-2 

Instrument details
Acronym MERSI-2
Full name Medium Resolution Spectral Imager -2
Purpose Multi-purpose imagery, including ocean colour
Short description 25-channel VIS/IR spectro-radiometer [see details in table below]
Background Replacing and merging MERSI-1 on FY-3A/3B and VIRR on FY-3A//3B/3C
Scanning Technique Cross-track: 2048 samples for channels at 1000 m resolution at nadir, or 8192 samples for channels at 250 m resolution, swath 2900 km - Along-track: ten 1-km lines every 1.5 s.
Resolution 250 m or 1.0 km at s.s.p.
Coverage / Cycle Global coverage once/day (VIS/NIR/SWIR channels), twice/day (MWIR/TIR).
Mass Power Data Rate

 

Providing Agency CMA
Instrument Maturity Backed by strong heritage
Utilization Period: 2018 to 2024
Last update: 2021-06-17
Detailed characteristics

Center wavelength

Bandwidth

SNR or NEΔT @ specified input

IFOV at s.s.p.

412 nm

20 nm

300 @ 44.9 W m-2 sr-1 μm-1

1000 m

443 nm

20 nm

300 @ 41.9 W m-2 sr-1 μm-1

1000 m

470 nm

50 nm

100 @ 35.3 W m-2 sr-1 μm-1

250 m

490 nm

20 nm

300 @ 32.1 W m-2 sr-1 μm-1

1000 m

550 nm

50 nm

100 @ 29.0 W m-2 sr-1 μm-1

250 m

555 nm

20 nm

500 @ 21 W m-2 sr-1 μm-1

1000 m

650 nm

50 nm

100 @ 22 W m-2 sr-1 μm-1

250 m

670 nm

20 nm

500 @ 10 W m-2 sr-1 μm-1

1000 m

709 nm

20 nm

500 @ 6.9 W m-2 sr-1 μm-1

1000 m

746 nm

20 nm

500 @ 9.6 W m-2 sr-1 μm-1

1000 m

865 nm

20 nm

500 @ 6.4 W m-2 sr-1 μm-1

1000 m

865 nm

50 nm

100 @ 25 W m-2 sr-1 μm-1

250 m

905 nm

20 nm

200 @ 10.0 W m-2 sr-1 μm-1

1000 m

936 nm

20 nm

100 @ 3.6 W m-2 sr-1 μm-1

1000 m

940 nm

50 nm

200 @ 15.0 W m-2 sr-1 μm-1

1000 m

1240 or 1030 nm

(1030 on FY-3F)

20 nm

100 @ 5.4 W m-2 sr-1 μm-1

1000 m

1380 nm

20 or 30 nm

(30 on FY-3F)

60/100 @ 6 W m-2 sr-1 μm-1

1000 m

1640 nm

50 nm

200 @ 7.3 W m-2 sr-1 μm-1

1000 m

2130 nm

50 nm

100 @ 1.2 W m-2 sr-1 μm-1

1000 m

3.80 μm

0.18 μm

0.25 K @ 270 K

1000 m

4.05 μm

0.155 μm

0.25 K @ 300/380 K

1000 m

7.20 μm

0.50 μm

0.30 K @ 270 K

1000 m

8.55 μm

0.30 μm

0.25 K @ 270 K

1000 m

10.8 μm

1.0 μm

0.4 K @ 300 K

250 m

12.0 μm

1.0 μm

0.4 K @ 300 K

250 m
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
  • Moderate resolution optical imager
WIGOS Subcomponents
  • Subcomponent 1
  • VIS/IR imagery; realisation of a Day/Night band [in SSO]
  • VIS/IR imager [in SSO]
  • Narrow-band or hyperspectral imagers
  • Narrow-band imager (for ocean colour)
Mission objectives
Primary mission objectives
  • Biomass
  • Cloud cover
  • Cloud optical depth
  • Cloud top height
  • Cloud top temperature
  • Cloud type
  • Fraction of Absorbed PAR (FAPAR)
  • Integrated Water Vapour (IWV)
  • Leaf Area Index (LAI)
  • Normalised Difference Vegetation Index (NDVI)
  • Sea surface temperature
  • Sea-ice cover
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
Aerosol column burden3 - highCloud sensitive.. Daylight only.VIS (with narrow bandwidth), NIR and SWIR channels including 760 nm for high-level aerosol
Aerosol effective radius3 - highCloud sensitive.. Daylight only.VIS (with narrow bandwidth), NIR (including 760 nm for high-level aerosol), and SWIR channels
Aerosol mass mixing ratio3 - highCloud sensitive.. Daylight only.VIS (with narrow bandwidth), NIR and SWIR channels including 760 nm for high-level aerosol
Aerosol Optical Depth3 - highCloud sensitive.. Daylight only.VIS (with narrow bandwidth), NIR and SWIR channels including 760 nm for high-level aerosol
Aerosol type3 - highCloud sensitive.. Daylight only.VIS (with narrow bandwidth), NIR and SWIR channels including 760 nm for high-level aerosol
Biomass*4 - fairCloud sensitive.. Index only.. Daylight only.VIS, NIR and SWIR channels. Biomass inferred from NDVI and LAI
Cloud cover*1 - primaryNo specific limitation.VIS, NIR, SWIR, MWIR and TIR channels
Cloud drop effective radius3 - highAt cloud top.. Daylight only.VIS, NIR, SWIR and MWIR channels (for differentiation)
Cloud ice effective radius3 - highAt cloud top.. Daylight only.VIS, NIR, SWIR and MWIR channels (for differentiation)
Cloud optical depth*3 - highLow-density cloud only.. Daylight only.VIS, NIR and SWIR channels
Cloud top height*3 - highNo specific limitation.TIR channels in window and water vapour band (for emissivity) to estimate cloud top height from its temperature
Cloud top temperature*2 - very highNo specific limitation.TIR channels in window and water vapour band (for emissivity)
Cloud type*1 - primaryNo specific limitation.VIS, NIR, SWIR, MWIR and TIR channels
Colour Dissolved Organic Matter (CDOM)4 - fairCloud sensitive.. Daylight only.Many narrow-bandwith VIS channels, suitable for more water types, in open ocean
Downward short-wave irradiance at Earth surface3 - highCloud sensitive.. Highly indirect.VIS, NIR and SWIR channels
Downward long-wave irradiance at Earth surface4 - fairCloud sensitive.. Highly indirect.MWIR and TIR channels including water vapour and CO2 bands
Earth surface albedo5 - marginalCloud sensitive.VIS channels
Fire fractional cover4 - fairCloud sensitive.. Coarse spatial resolution.VIS, MWIR and TIR channels
Fire radiative power2 - very highCloud sensitive.. Coarse spatial resolution.MWIR and TIR channels
Fire temperature2 - very highCloud sensitive.. Coarse spatial resolution.MWIR and TIR channels
Fraction of Absorbed PAR (FAPAR)*3 - highCloud sensitive.VIS channels including Red at 700 nm
Land surface temperature3 - highCloud sensitive.MWIR and TIR window channels (high sensitivity to high temperature, cloud impact reduction, water vapour correction)
Leaf Area Index (LAI)*2 - very highCloud sensitive.. Daylight only.VIS, NIR and SWIR channels
Normalised Difference Vegetation Index (NDVI)*3 - highCloud sensitive.VIS and NIR channels
Ocean chlorophyll concentration 4 - fairCloud sensitive.. Daylight only.Many narrow-bandwith VIS channels, suitable for more water types, in open ocean
Ocean Diffuse Attenuation Coefficient (DAC)4 - fairCloud sensitive.. Daylight only.Many narrow-bandwith VIS channels, suitable for more water types, in open ocean
Ocean suspended sediments concentration4 - fairCloud sensitive.. Daylight only.Many narrow-bandwith VIS channels, suitable for more water types, in open ocean
Oil spill cover5 - marginalCloud sensitive.. Daylight only.VIS channels with narrow bandwidth
Photosynthetically Active Radiation (PAR)3 - highCloud sensitive.VIS channels, range accurately sampled
Sea surface temperature*2 - very highCloud sensitive.MWIR and TIR window channels around 3.7 and 11 micrometers (cloud impact reduction, water vapour correction)
Short-wave cloud reflectance4 - fairNo specific limitation.VIS, NIR and SWIR channels
Snow cover2 - very highCloud sensitive.. Daylight only.VIS, NIR and SWIR channels, enabling screening snow from clouds
Soil moisture at surface4 - fairCloud sensitive.. Index only.VIS, SWIR, MWIR and TIR channels. Soil moisture inferred from differential brightness and thermal inertia
Specific humidity4 - fairCloud sensitive.. Very coarse vertical resolution.. Daylight only.NIR channels in the ro-sigma-tau band of water vapour around 940 nm
Integrated Water Vapour (IWV)*2 - very highCloud sensitive.NIR and TIR channels around 940 nm, 6.3 micrometers and in the 11 micrometers split window
Upward short-wave irradiance at TOA5 - marginalSpectral interpolation needed.. Information on BRDF needed.VIS, NIR and SWIR channels
Upward long-wave irradiance at TOA4 - fairSpectral interpolation needed.MWIR and TIR channels in windows around 3.7 and 11 micrometers, and in water vapour and CO2 bands around 4.3 and 6.3 micrometers
Upward long-wave irradiance at Earth surface4 - fairCloud 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 and 6.3 micrometers
Aerosol volcanic ash3 - highCloud sensitive.. Daylight only.VIS, NIR and SWIR channels including 760 nm for high-level ashes
Aerosol volcanic ash Total Column3 - highCloud sensitive.. Daylight only.VIS, NIR and SWIR channels including 760 nm for high-level ashes
Wind (horizontal)4 - fairLimited to high latitudes.. Cloud or water vapour tracers needed.TIR channels in the 11 micrometers window and the 6.3 micrometers water vapour band
Sea-ice cover*1 - primaryCloud sensitive.VIS, NIR (for contour enhancement), SWIR (for discrimination from clouds), MWIR and TIR channels