Clouds and the Earth’s Radiant Energy System (CERES)




CERES

Clouds and the Earth’s Radiant Energy System

Satellites

TRMM, EOS-Terra, EOS-Aqua, NPP and NPOESS-1

Status

Operational – Utilised in the period 1997 to ~ 2020

Mission

Earth radiation budget

Instrument type

Two broad-band and one narrow-band channel radiometer.  Two units, one cross-track scanning, one bi-axial scanning for irradiance computation (only one unit on TRMM, alternatine the two modes)

Scanning technique

Cross-track: 80 steps of 20 km s.s.p., swath 3000 km - Along-track: one 20-km line every 3 s.
Bi-axial scanning by rotating azimuth while cross-nadir scanning

Coverage/cycle

Global coverage twice/day (IR and total radiance) or once/day (short-wave)

Resolution (s.s.p.)

20 km (10 km for TRMM due to lower orbit)

Resources

Mass: 100 kg - Power: 103 W - Data rate: 20 kbps

Channel

Spectral interval

Noise Equivalent Radiance

Absolute accuracy

SNR

Narrow-band

8 - 12 µm

0.3 W m-2 sr-1

0.3 W m-2 sr-1

..............

Short-wave

0.3 - 5.0 µm

0.3 W m-2 sr-1

0.8 W m-2 sr-1

.............

Total radiance

0.3 - 100 µm

0.3 W m-2 sr-1

0.6 W m-2 sr-1

.............

Last updated in June 2008