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About Aqua
Image of CERES instrument

The Cloud's and the Earth's Radiant Energy System (CERES) is a 3-channel radiometer measuring reflected solar radiation in the 0.3-5 µm wavelength band, emitted terrestrial radiation in the 8-12 µm band, and total radiation from 0.3 µm to beyond 100 µm. These data are being used to measure the Earth's total thermal radiation budget, and, in combination with MODIS data, detailed information about clouds. The first CERES instrument was launched on the Tropical Rainfall Measuring Mission (TRMM) satellite in November 1997; the second and third CERES instuments were launched on the Terra satellite in December 1999; and the fourth and fifth CERES instruments are on board the Aqua satellite.

Instrument Characteristics
  • Selected for flight on TRMM, Terra, and Aqua.
  • Two broadband, scanning radiometers: One cross-track mode, one rotating azimuth plane (bi-axial scanning).
  • First instrument (cross-track scanning) is continuing ERBE, TRMM, and Terra measurements and the second (biaxially scanning) is providing angular radiance information to improve the accuracy of angular models used to derive the Earth's radiative balance.
  • Single scanner on TRMM mission (launched Nov. 1997)
  • Dual scanners on Terra (launched Dec. 1999) and Aqua, and single thereafter.

Instrument Facts

Heritage   Earth Radiation Budget Experiment (ERBE)
Prime Contractor   TRW
Responsible Center   NASA Langley Research Center
Three Channels in Each Radiometer   Total radiance (0.3 to 100 µm); Shortwave (0.3 to 5 µm); Window (8 to 12 µm)
Swath   Limb to limb
Spatial Resolution   20 km at nadir
Mass   50 kg per scanner
Duty Cycle   100%
Power   47 W (average) per scanner, 104 W (peak: biaxial mode) both scanners
Data Rate   10 kbps per scanner
Thermal Control By   Heaters, radiators
Thermal Operating Range   38±0.1°C (detectors)
Field of View (FOV)   ±78° cross-track, 360° azimuth
Instrument Instantaneous FOV   14 mrad
Pointing Requirements (platform + instrument 3σ)
Control   720 arcsec
Knowledge   180 arcsec
Stability   79 arcsec/6.6 sec
Physical Size   60 x 60 x 57.6 cm/unit

"CERES Scans the Globe"

There are two CERES on Aqua, following two on the Terra satellite, launched in 1999, and one on the Tropical Rainfall Measuring Mission, launched in 1997. This artist's concept animation shows the CERES instruments (one in cross-track scan mode, the other in biaxial scan mode) measuring heat emitted (outgoing longwave radiation) to space from Earth's surface.



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NASA Official: Claire Parkinson
Last Updated: April 10, 2014 at 3:14 PM