BackForwardInstrument:  RBI 

Instrument details
Acronym RBI
Full name Radiation Budget Instrument
Purpose Earth radiation budget
Short description Three broad-band channels, for total, SW and LW radiation respectively. Capability of bi-axial scanning for irradiance computation [see detailed characteristics below]
Background Follow-on of CERES flown in different configurations on TRMM, EOS-Terra, EOS-Aqua and SNPP
Scanning Technique Two modes: 1) cross-track: 80 steps of 20 km s.s.p., swath 3000 km, along-track: one 20-km line every 3 s; or 2) bi-axial scanning by rotating azimuth while cross-nadir scanning.
Resolution 30 km
Coverage / Cycle Global coverage twice/day (IR and total radiance) or once/day (short-wave)
Mass Power Data Rate


Providing Agency NOAA
Instrument Maturity Flown on operational programme
Utilization Period: ≥2023 to ≥2029
Last update: 2021-06-02
Detailed characteristics


Spectral interval      

Noise Equivalent Radiance

Absolute accuracy



0.3-5.0 µm

0.3 W m-2 sr-1

0.8 W m-2 sr-1


Total radiance

0.3-100 µm

0.3 W m-2 sr-1

0.6 W m-2 sr-1



5-50 µm

0.3 W m-2 sr-1

0.3 W m-2 sr-1


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
  • Broadband Earth radiation radiometer
WIGOS Subcomponents
  • Subcomponent 1
  • Broadband radiometer (for ERB)
Mission objectives
Primary mission objectives
  • Upward long-wave irradiance at TOA
  • Upward short-wave irradiance at TOA
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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
Upward short-wave irradiance at TOA1 - primaryNo specific limitation.SW, LW and Total (SW+LW) broadband channels with cross-track and bi-axial scanning for BRDF necessary for irradiance computation
Upward long-wave irradiance at TOA1 - primaryNo specific limitation.SW, LW and Total (SW+LW) broadband channels