BackForwardInstrument:  CERES 

Instrument details
Acronym CERES
Full name Clouds and the Earth’s Radiant Energy System
Purpose Earth radiation budget
Short description
  • Two broad-band and one total irradiance channels. Capability of bi-axial scanning for irradiance computation [see detailed characteristics below]
  • More information here
Background

Flown in different configurations: one unit used either for cross-nadir or bi-axial scanning on TRMM (instrument early failure), and on JPSS-1; two units for simultaneous cross-nadir and bi-axial scanning on EOS-Terra, EOS-Aqua and Suomi-NPP
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 57 kg Power 50 W Data Rate 10 kbps

 

Providing Agency NASA
Instrument Maturity Flown on operational programme
Utilization Period: 1998 to 2031
Last update: 2024-09-30
Detailed characteristics
Channel Spectral interval       Noise Equivalent Radiance Absolute accuracy SNR
Short-wave 0.3 - 5.0 µm 0.3 W m-2 sr-1 0.8 W m-2 sr-1 225
Total radiance 0.3 - 100 µm 0.3 W m-2 sr-1 0.6 W m-2 sr-1 750
TIR

8 - 12 µm

 0.3 W m-2 sr-1 0.3 W m-2 sr-1 750
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
  • Absolutely calibrated broadband radiometers, and TSI and SSI radiometers
  • Broadband radiometer (for ERB)
Mission objectives
Primary mission objectives
  • Upward long-wave irradiance at TOA
  • Upward short-wave irradiance at TOA
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
Upward short-wave irradiance at TOA*1 - primaryNo specific limitation.SW and Total (SW+LW) broadband channels. Cross-track and bi-axial scanning for BRDF. Supporting narrow-bandwidth channel(s)
Upward long-wave irradiance at TOA*2 - very highNo specific limitation.SW and Total (SW+LW) broadband channels with supporting narrow-bandwidth channel(s). LW computed as difference Total - SW