THE CEOS DATABASE : Missions, Instruments and Measurements
CEOS EO HANDBOOK – MEASUREMENT INSTRUMENTS
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 ].
InstrumentStatus/
Accuracy
Instrument DescriptionMeasurement TechnologyTimeline
CHRIS
Compact High Resolution Imaging Spectrometer
Operational
Supports a range of land, ocean and atmospheric applications, including agricultural science, forestry, environmental science, atmospheric science and oceanography.n/a
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 (HJ-1A)
Hyper Spectrum Imager
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 GMES 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
Vegetation
Vegetation
Operational
Global coverage every two days for uses including climate impact assessments, surface water resource management, agricultural monitoring, and food security estimates.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
* Description adapted from WMO.
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