The Earth Radiation Budget Experiment (ERBE)

The Earth Radiation Budget Experiment (ERBE) is the first multisatellite system designed to measure the Earth's radiation budget. It will fly on a low-inclination NASA satellite and two Sun-synchronous NOAA satellites during the mid-1980s. Each satellite will carry two instrument packages—a scanner and a nonscanner—each package containing a complete, traceable system for inflight calibration. The nonscanner package has four Earth-viewing channels, as well as a solar monitor similar to that flown on the Solar Max Mission. The nonscanner detectors are the first Earth-viewing active cavity radiometers. The scanner package contains three thermistor bolometers which scan the Earth perpendicular to the orbital track. The data from the satellite radiometers will be brought to the top of the atmosphere using a pixel-by-pixel process for the scanner data and a numerical filter for the nonscanner. The inversion will use angular directional models based on the Nimbus 7 ERB instruments, selecting the appropriate model for cloud conditions from the ERBE scanner data. After the measurements have been brought to the top of the atmosphere, they will be averaged over time to produce monthly averages. In averaging, allowance will be made for meteorological variations, as well as albedo variations with solar zenith angle. These new features are expected to provide a substantial improvement in the accuracy of the radiation budget on regional as well as global scales. This paper also provides a brief description of the implementation of the ERBE Project, including the ERBE Science Team.