BackForwardInstrument:  SIM-1 

Instrument details
Acronym SIM-1
Full name Solar Irradiance Monitor - 1
Purpose Total solar irradiance
Short description Three cavity radiometers.  Spectral range: 0.2-50 µm, Noise Equivalent Radiance 0.2  W m-2 sr-1, absolute accuracy 0.5 %
Background New development
Scanning Technique Viewing the Sun when the satellite is in the north pole area (no tracking)
Resolution N/A (sun pointing)
Coverage / Cycle One measurement sequence on each orbit; thus 100 min
Mass 14.7 kg Power 9.5 W Data Rate 16 kbps


Providing Agency CMA
Instrument Maturity Flown on operational programme
Utilization Period: 2008 to 2020
Last update: 2021-06-23
Detailed characteristics
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
  • Solar irradiance monitor
WIGOS Subcomponents
  • Subcomponent 1
  • Absolutely calibrated broadband radiometers, and TSI and SSI radiometers
  • TSI and SSI radiometers (for solar irradiance)
Mission objectives
Primary mission objectives
  • Downward 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
Downward short-wave irradiance at TOA*2 - very highNo specific limitation.TSI over the range from UV to FIR