Inter-Comparisons of SNPP, NOAA-20, and NOAA-21 OMPS Nadir Mapper and Nadir Profiler SDR Earth-View Radiance Values with TROPOMI

The Ozone Mapping and Profiler Suite (OMPS) Nadir Mapper (NM) and Nadir Profiler are ultraviolet and visible spectrometers that measure spectra in the 300nm to 380nm range and 250nm to 310nm range, respectively, from both Earth radiance and solar irradiance. The OMPS NM and NP instruments are currently in orbit aboard three different satellites: the Suomi National Polar-orbiting Partnership (SNPP), NOAA-20, and NOAA-21. These sensors allow for robust, overlapping Sensor Data Record (SDR) datasets to be created, but it is important to analyze how these datasets compare to those from similar satellite instruments. The TROPOspheric Monitoring Instrument (TROPOMI) is one such instrument.

TROPOMI is on board the Copernicus Sentinel-5 Precursor satellite and consists of ultraviolet, visible, near-infrared, and short-wave infrared spectrometers that measure radiance values intermittently between 267 and 2389 nm. This broad spectrum is separated into different radiance bands, with two bands in particular, bands 2 and 3, covering a range of 300nm to 400nm. This range overlaps the entirety of the OMPS NM spectrum, as well as the overlap region between OMPS NM and NP.

This study explores two different methods that were used to compare data from OMPS and TROPOMI. One method focuses on comparing broader measurements over tropical open ocean regions. This method was used to compare the entire spectrum of OMPS NM with TROPOMI, and was also used to compare data in the overlap region between OMPS NM and NP and TROPOMI band 2 data, between 300nm and 310nm. The second method uses a ray-matching technique in the polar regions to compare individual datapoints with the most similar viewing conditions possible. This method was used solely for OMPS-NM and TROPOMI. Preliminary results from these comparisons have indicated that OMPS and TROPOMI are performing consistently with each other, independent of the comparison method used.

Disclaimer: the presentation contents are solely the opinions of the authors and do not constitute a statement of policy, decision, or position on behalf of NOAA or the U. S. Government.

Acknowledgement: Thanks to Dr. Chunhui Pan for her long-term contributions to the OMPS SDR calibration and reprocessing projects. Thanks to Dr. Larry Flynn for his continued support of this study. Thanks to Mr. Eric Beach for collecting historical OMPS SDR data sets that are used in the study.