Characterization of the Nimbus-7 SBUV Radiometer for the Long-Term Monitoring of Stratospheric Ozone

Precise knowledge of in-orbit sensitivity change is critical for the successful monitoring of stratosphere ozone by satellite-based remote sensors. This paper evaluates those aspects of the in-flight operation that influence the long-term stability of the upper stratosphere ozone measurements made by the Nimbus-7 SBUV spectroradiometer and chronicles methods used to maintain the long-term albedo calibration of this UV sensor. It is shown that the instrument's calibration for the ozone measurement, the albedo calibration, has been maintained over the first 6 yr of operation to an accuracy of approximately ±2%. The instrument's wavelength calibration is shown to drift linearly with time. Knowledge of the SBUV wavelength assignment is maintained to a 0.02 mm precision.