Nadir ultraviolet imaging spectrometer for the NPOESS Ozone Mapping and Profiler Suite (OMPS)

The Ozone Mapping and Profiler Suite (OMPS) is being developed for the United States National Polar-orbiting Operational Environmental Satellite System (NPOESS). We describe the optical design and predict the performance of the OMPS nadir-looking imaging spectrometer. Backscattered solar ultraviolet radiation is dispersed and measured to determine the ozone total column amounts and profile concentrations. The sensor consists of a wide field (110 degree) telescope, with a solar-diffuser calibration mechanism, and two spectrometers: an imager covering 300 to 380 nm with a 50 km nadir footprint for mapping total column ozone across a 2800 km swath, and a 250 to 310 nm spectrometer with a single 250 km footprint to provide ozone profile data with SBUV/2 heritage. Both spectrometers provide 1 nm resolution (full-width at half-maximum, FWHM) spectra and handle the demanding dynamic range of the backscattered solar radiation with the required sensitivity for ozone retrievals.