BackForwardInstrument:  ERM-2 

Instrument details
Acronym ERM-2
Full name Earth Radiation Measurement - 2
Purpose Earth radiation budget
Short description
  • ERM-II is a radiometer with 3 broadband channels that measure the earth-reflected solar flux and earth-emitted thermal flux over total (0.2~100μm), long (5~50μm) and short (0.2~5.0μm) wavebands. Long term stability <1.5%.
  • Calibration monitoring here
Background

Evolution of ERM-1 flown on FY 3A, 3B, 3C. Improvements over ERM-1 are (1) calibration with solar and lunar source; (2) Additional LW channel; (3) radiometric noise reduced.
Scanning Technique

Cross-track scanning ±56 deg.
Resolution FoV 2 x 2 deg
Coverage / Cycle Global coverage twice/day (total radiance) or once/day (short-wave).
Mass Power Data Rate

 

Providing Agency CMA
Instrument Maturity Backed by strong heritage
Utilization Period: 2023 to 2029
Last update: 2024-09-09
Detailed characteristics
Spectral range  0.2～5.0 μm 5.0～50 μm 0.2～100 μm
Radiance range 0～280 Wm-2Sr-1 0～120 Wm-2Sr-1 0～400 Wm-2Sr-1
Calibration accuracy 1% 0.5% 0.5%
Sensitivity 0.3 Wm-2Sr-1 0.2 Wm-2Sr-1 0.2 Wm-2Sr-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
  • 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.LW and Total (SW+LW) broadband channels. SW computed as difference Total - LW. Cross-track and bi-axial scanning for BRDF. Supporting narrow-bandwidth channel(s)
Upward long-wave irradiance at TOA*1 - primaryNo specific limitation.LW and Total (SW+LW) broadband channels with supporting narrow-bandwidth channel(s)