Description
A multiple channel radiation imager, one of the primary instruments onboard FY-4. Technically featured by precisely designed two-mirror structure, capable of accurate and flexible sensing in two dimensions, and minute-level fast sector scanning. Frequent earth imaging over 14 bands with off-axis three reflections of primary optic system. On-board black body available for IR calibrations at very short time intervals.
Satellite |
FY-4A FY-4B |
Weight |
306kg |
Number of channels |
FY-4A: 14, FY-4B: 15 |
Spatial resolution |
0.5~1 km (VIS/near IR), 2~4 km (IR) |
Time for full-disc scanning |
15 min |
Time for sector scanning |
1min (1000km × 1000km) |
Sensitivity |
S/N>3 @ 1% (reflection bands) NE∆T: 0.2K @ 300K (IR bands) |
Characteristics (FY-4A)
Channel |
Type |
Central wavelength |
Band |
SNR or NEΔT @ specified input |
Spatial resolution |
Main purpose |
1 |
Visible & Near-Infrared |
0.47µm |
0.45~0.49µm |
S/N≥90 @ ρ=100% |
1km |
Aerosol |
2 |
0.65µm |
0.55~0.75µm |
S/N≥200 @ ρ=100% |
0.5~1km |
Fog, cloud |
3 |
0.825µm |
0.75~0.90µm |
S/N≥200 @ ρ=100% |
1km |
Vegetation |
4 |
Short-wave Infrared |
1.375µm |
1.36~1.39µm |
S/N≥90 @ ρ=100% |
2km |
Cirrus |
5 |
1.61µm |
1.58~1.64µm |
S/N≥200 @ ρ=100% |
2km |
Cloud, snow |
6 |
2.25µm |
2.1~2.35µm |
S/N≥200 @ ρ=100% |
2~4km |
Cirrus, aerosol |
7 |
Mid-wave Infrared |
3.75µm |
3.5~4.0µm (high) |
NEΔT≤0.7K @ 300K |
2km |
Fire |
8 |
3.75µm |
3.5~4.0µm (low) |
NEΔT≤0.2K @ 300K |
4km |
Land surface |
9 |
Water vapor |
6.25µm |
5.8~6.7µm |
NEΔT≤0.3K @ 260K |
4km |
High level water vapor |
10 |
7.1µm |
6.9~7.3µm |
NEΔT≤0.3K @ 260K |
4km |
Middle level water vapor |
11 |
Long-wave Infrared |
8.5µm |
8.0~9.0µm |
NEΔT≤0.2K @ 300K |
4km |
Water vapor, cloud |
12 |
10.7µm |
10.3~11.3µm |
NEΔT≤0.2K @ 300K |
4km |
Surface temperature |
13 |
12.0µm |
11.5~12.5µm |
NEΔT≤0.2K @ 300K |
4km |
Surface temperature |
14 |
13.5µm |
13.2~13.8µm |
NEΔT≤0.5K @ 300K |
4km |
Cloud thickness |
AGRI transmittance over wavelength
AGRI scan range (105°E)
Data and Products
Calibration and Validation
AGRI calibration and validation
FY-4B AGRI SRF (ZIP)
FY-4A AGRI SRF (408KB)