| CEOS EO HANDBOOK – MEASUREMENT INSTRUMENTS
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Measurements > Land >
Albedo and reflectance >
Photosynthetically Active Radiation (PAR)
  | Measurement Definition*: Flux of downwelling photons of wavelength 0.4-0.7 µm at surface - Physical unit: [ µ einstein ٠ m-2 s-1 ] (1 einstein = 6 ٠ 1023 photons); most frequently used: [ W/m2 ] - Accuracy unit: [ W/m2 ]. |
| Instrument | Status/
Accuracy | Instrument Description | Measurement Technology | Timeline |
EPIC
Earth Polychromatic Imaging Camera | Operational
| Diurnal measurements of ozone, sulfur dioxide, UV surface radiation, clouds, aerosols and vegetation. | Multi-purpose imaging Vis/IR radiometer |  |
HSI-2 (HJ-2A)
Hyper Spectrum Imager 2 | Operational
| Hyperspectral measurements for environment and disaster management operations. | Multi-purpose imaging Vis/IR radiometer | |
MODIS
MODerate-Resolution Imaging Spectroradiometer | Operational
| Data on biological and physical processes on the surface of the Earth and in the lower atmosphere, and on global dynamics. Surface temperatures of land and ocean, chlorophyll fluorescence, land cover measurements, cloud cover (day and night). | n/a | |
MSI (Sentinel-2)
Multi-Spectral Instrument (Sentinel-2) | Operational
| Optical high spatial resolution imagery over land and coastal areas for Copernicus operational services. | n/a | |
OLCI
Ocean and Land Colour Imager | Operational
| Marine and land services. | n/a | |
SGLI
Second-generation Global Imager | Operational
+/-15 % | Medium resolution multi-spectral imaging of land, ocean and atmosphere. SGLI-VNR is an optical sensor capable of multi-channel nadir observation at wavelengths from near-UV to NIR and forward or backward polarization observation at red and near infrared wavelengths (Push-broom scanning). SGLI-IRS is an optical sensor capable of multi-channel nadir observation at wavelengths from SWIR to TIR wavelengths (Cross-track scanning). | n/a | |
VSC
Venus Superspectral Camera | Operational
| High resolution superspectral images (12 spectral bands) for vegetation and landcover applications. | n/a | |
VIS-NIR
Multi-spectral Optical Camera - Visible & Near Infrared | Approved
| Ocean Colour - Open ocean, coastal & in-land waters. | n/a | |
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* Description adapted from WMO.
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