CALIBRATION PLANS FOR THE MULTI-ANGLE IMAGING SPECTRORADIOMETER (MISR)

The EOS Multi-angle Imaging SpectroRadiometer (MISR) will study the ec ology and climate of the Earth through acquisition of global multi-ang le imagery. The MISR employs nine discrete cameras, each a push-broom imager. Of these, four point forward, four point aft and one views the nadir. Absolute radiometric calibration will be obtained pre-flight u sing high quantum efficiency (HQE) detectors and an integrating sphere source. After launch, instrument calibration will be provided using H QE detectors in conjunction with deployable diffuse calibration panels . The panels will be deployed at time intervals of one month and used to direct sunlight into the cameras, filling their fields-of-view and providing through-the-optics calibration. Additional techniques will b e utilized to reduce systematic errors, and provide continuity as the methodology changes with time. For example, radiation-resistant photod iodes will also be used to monitor panel radiant exitance. These data will be acquired throughout the five-year mission, to maintain calibra tion in the latter years when it is expected that the HQE diodes will have degraded. During the mission, it is planned that the MISR will co nduct semi-annual ground calibration campaigns, utilizing field measur ements and higher resolution sensors (aboard aircraft or in-orbit plat forms) to provide a check of the on-board hardware. These ground calib ration campaigns are limited in number, but are believed to be the key to the long-term-maintenance of MISR radiometric calibration.