Characterization of the Earth Radiation Budget Experiment radiometers

The Earth Radiation Budget Experiment (ERBE) scanning radiometers were used to measure the earth's radiation fields during the period November 1984 through February 1990. The ERBE radiometric packages were placed into orbit aboard the Earth Radiation Budget Satellite (ERBS) and the NOAA-9 and NOAA-10 spacecraft platforms. In each radiometric package, thermistor bolometers were used as detection elements for the broadband total (0,2 - 50,0 microns), shortwave (0,2 - 5,0 microns), and longwave (5,0 - 50,0 microns) spectral regions. Flight calibration facilities were built into each of the spacecraft radiometric packages. The flight facilities consisted of black bodies, tungsten lamps, and silicon photodiodes. The black bodies and tungsten lamps were found to be reliable at precision levels approaching 0,5 percent over a five-year period. The photodiodes were found to degrade more than 2 percent during the first year in orbit. In this paper, the flight calibration systems for the ERBE scanning radiometers are described along with the resultant measurements.