Earth Radiation Measurement-I (ERM-I)


Global monitoring of the Earth radiation, one of the missions of FY-3 satellite, is carried out by two instruments: the Earth Radiation Measurement (ERM) and the Solar Irradiance Monitor (SIM). Two products are generated from the measurement: the solar constant and the earth reflected shortwave and emitted long-wave radiative flux at the top of the atmosphere. The ERM-I is a radiometer with 2 broadband channels that measure the earth-reflected solar flux and earth-emitted thermal flux over total (0.2-50μm) and short (0.2-4.3μm) wavebands in two observing modes. The cross-track scanning mode is possible for spatial resolution of 28km with 2-degree NFOVs, while the nadir staring mode is with 120 degree WFOVs.

Satellite FY-3A , FY-3B , FY-3C 
Mission Earth radiation budget
Instrument type Tow broad-band channels radiometer
Scanning technique Scanner: Swath 2200km cross-track scanning, 151 steps
Non-scanner: 120 degree angle
Time resolution Scanner: a scan takes 4s
Non-scanner: 2 samples per second
Spatial resolution 28 km (scanner)


Channel Spectral interval Noise Equivalent Radiance Absolute accuracy SNR
Short-wave 0.2~4.3 µm 0.4 W⋅m-2⋅sr-1 1.5 W⋅m-2⋅sr-1 900
Total radiance 0.2~50 µm 0.4 W⋅m-2⋅sr-1 1.1 W⋅m-2⋅sr-1 1250

Data and Products

Satellite Instrument Datasets
FY-3C ERM-I L1 data
FY-3B ERM-I L1 data
FY-3A ERM-I L1 data

Calibration and Validation

ERM-I calibration and validation