Analysis of OMPS in-flight CCD dark current degradation

Abstract

This paper presents the in-flight charge-coupled device (CCD) dark characterization of the Suomi National Polar-orbiting Partnership (S-NPP) Ozone Mapping Profiler Suite (OMPS). Data from OMPS's three different CCD detector arrays have been collected to characterize in-flight detector behaviors. It is of our primary interest in the evolution and trend of the dark current as well as the signal distribution beyond the first 4 years of the mission. Based on in-situ measurements obtained during the prelaunch calibration, we monitor changes in the CCD dark current on the pixel level in order to validate the in-flight OMPS dark calibration. The dark current change along with the Random Telegraph Signal (RTS) and the South Atlantic Anomaly (SAA) are studied while focusing on the influence of the Sensor Data Record's quality in terms of radiance errors. Our results show that current in-flight dark calibration provides reasonable Sensor Data Records (SDRs) and Environmental Data Records (EDRs) with an error of less than ∼0.1% on average in the earth-view radiance. However, calibration error inside of the SAA region of influence due to transients is sizable for wavelengths less than 302 nm where the signal-to-noise ratio is low.