Ozone Mapper Profiler Suite Nadir Profiler Degradation

Abstract

The Ozone Mapping and Profiler Suite (OMPS) measures ozone concentration in the Earth atmosphere. There are two OMPS units currently flying on board the Suomi NPP and NOAA-20 spacecrafts, respectively. OMPS Sensor Data Records provide users with Earth view radiances from Earth science observation and Solar irradiance via solar observations. OMPS solar observations provide time-dependent measurements of the solar flux over mission times. They also provide information on wavelength variations over the sensors' lifetimes. The solar observations are made through two diffusers at the telescope entrance aperture, a reflective working diffuser for short-term monitoring and a reflective reference diffuser for long-term monitoring of sensor stability. Data collected from the solar observation are used to improve the quality of ozone and other products and maintain the sensor data calibration quality over sensor lifetime. Routine solar calibration adjustments have been conducted for the two Nadir Profiler (NP) sensors in a timeline with the solar measurements via their own solar diffusers. The calibration minimizes the wavelength scale error variations to less than <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pm 0.01\text{nm}$</tex> . A recent improvement will be made to correct for instrument optical degradation which was determined through the changes in the instruments' throughput. These may be as large as to 2.2% for Suomi-NPP NP, and 1.2% for NOAA-20 NP over their current lifetimes.