BackForwardInstrument:  MERSI-1 

Instrument details
Acronym MERSI-1
Full name Medium Resolution Spectral Imager -1
Purpose Ocean colour, vegetation indexes and aerosol
Short description
  • 20 channels, 19 narrow-bandwidth in VIR/NIR/SWIR and one broadband in the Thermal IR [see detailed characteristics below]
  • Calibration monitoring here
Background

New development
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 in 1 day (in daylight)
Mass 117 kg Power 125 W Data Rate 16 Mbps

 

Providing Agency CMA
Instrument Maturity Flown on operational programme
Utilization Period: 2008 to 2021
Last update: 2024-09-09
Detailed characteristics

Center wavelength

Bandwidth

SNR or NEρ 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 @ 50% albedo

250 m

490 nm

20 nm

300 @ 32.1 W m-2 sr-1 μm-1

1000 m

520 nm

20 nm

500 @ 29.0 W m-2 sr-1 μm-1

1000 m

550 nm

50 nm

100 @ 50% albedo

250 m

565 nm

20 nm

500 @ 21.0 W m-2 sr-1 μm-1

1000 m

650 nm

50 nm

100 @ 50% albedo

250 m

650 nm

20 nm

500 @ 10.0 W m-2 sr-1 μm-1

1000 m

685 nm

20 nm

0.05 %

1000 m

765 nm

20 nm

0.05 %

1000 m

865 nm

20 nm

0.05 %

1000 m

865 nm

50 nm

100 @ 50% albedo

250 m

905 nm

20 nm

0.10 %

1000 m

940 nm

20 nm

0.10 %

1000 m

980 nm

20 nm

0.10 %

1000 m

1030 nm

20 nm

0.10 %

1000 m

1640 nm

50 nm

0.08 %

1000 m

2130 nm

50 nm

0.07 %

1000 m

11.50 μm

2.50 μm

0.3 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
  • Narrow-band or hyperspectral imagers
  • Narrow-band imager (for ocean colour)
Mission objectives
Primary mission objectives
  • Aerosol Optical Depth
  • Aerosol column burden
  • Biomass
  • Cloud cover
  • Cloud optical depth
  • Earth surface albedo
  • Fraction of Absorbed PAR (FAPAR)
  • Integrated Water Vapour (IWV)
  • Leaf Area Index (LAI)
  • Normalised Difference Vegetation Index (NDVI)
  • Sea surface temperature
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 burden*3 - 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 Depth*3 - 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*3 - highNo specific limitation.VIS, NIR and TIR channels
Cloud optical depth*3 - highLow-density cloud only.. Daylight only.VIS, NIR and SWIR channels
Cloud top height5 - marginalDaylight only.NIR channels to estimate the total-column O2 above the cloud top as measured around 760 nm
Cloud top temperature5 - marginalNo specific limitation.TIR window channel(s)
Cloud type2 - very highNo specific limitation.VIS, NIR, SWIR 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
Earth surface albedo*5 - marginalCloud sensitive.VIS channels
Fire fractional cover4 - fairCloud sensitive.. Coarse spatial resolution.VIS and TIR channels
Fire radiative power5 - marginalCloud sensitive.. Coarse spatial resolution.TIR channels
Fire temperature5 - marginalCloud sensitive.. Coarse spatial resolution.TIR channels
Fraction of Absorbed PAR (FAPAR)*3 - highCloud sensitive.VIS channels including Red at 700 nm
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*5 - marginalCloud sensitive.TIR window channel(s) around 11 micrometers .
Sea-ice cover2 - very highCloud sensitive.VIS, NIR (for contour enhancement), SWIR (for discrimination from clouds) and TIR channels
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, NIR, SWIR 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)*4 - fairCloud sensitive.. Daylight only.NIR channels in the bands of water vapour around 900 nm and 940 nm
Upward short-wave irradiance at TOA5 - marginalSpectral interpolation needed.. Information on BRDF needed.VIS, NIR and SWIR channels
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)5 - marginalLimited to high latitudes.. Cloud or water vapour tracers needed.TIR channel(s) around 11 micrometers window