Postlaunch performance of the Suomi National Polar‐orbiting Partnership Ozone Mapping and Profiler Suite (OMPS) nadir sensors

Abstract

The prelaunch specifications for nadir sensors of the Ozone Mapping and Profiler Suite (OMPS) were designed to ensure that measurements from them could be used to retrieve total column ozone and nadir ozone profile information both for operational use and for use in long-term ozone data records. In this paper, we will show results from our extensive analysis of the performance of the nadir mapper (NM) and nadir profiler (NP) sensors during the first year and a half of OMPS nadir operations. In most cases, we determined that both sensors meet or exceed their prelaunch specifications. Normalized radiance (radiance divided by irradiance) measurements have been determined to be well within their 2% specification for both sensors. In the case of stray light, the NM sensor is within its 2% specification for all but the shortest wavelengths, while the NP sensor is within its 2% specification for all but the longest wavelengths. Artifacts that negatively impacted the sensor calibration due to diffuser features were reduced to less than 1% through changes made in the solar calibration sequence. Preliminary analysis of the disagreement between measurements made by the NM and NP sensors in the region where their wavelengths overlap indicates that it is due to shifts in the shared dichroic filter after launch and that it can be corrected. In general, our analysis indicates that both the NM and NP sensors are performing well, that they are stable, and that any deviations from nominal performance can be well characterized and corrected.

First results from a rotational Raman scattering cloud algorithm applied to the Suomi National Polar-orbiting Partnership (NPP) Ozone Mapping and Profiler Suite (OMPS) Nadir Mapper

“…This analysis also shows a shift (0.06 nm or less) in wavelength between the radiance and irradiance measurements that, if left uncorrected, will cause errors in the normalized radiance. We account for this shift through a term in our fitting algorithm; results from this term agree well with results shown in Seftor et al (2014). Furthermore, analysis of the resulting Level 2 ozone products validate their performance as well (Kramarova et al, 2013).…”

Characterization and correction of OMPS nadir mapper measurements for ozone profile retrievals

“…This analysis indicates that the accuracy of wavelength registration in ozone fitting wavelengths is 0.03-0.06 nm for earthshine measurements and < 0.02 nm for solar measurements with consistent variation over all cross-track pixels. These wavelength errors are larger than those reported by Seftor et al (2014) due to different fitting windows. They use 350-380 nm where prominent solar Fraunhofer absorption lines exist and the interference with ozone absorption lines are negligible.…”

“…The data consist of calibrated Earth-view radiance and solar irradiance data measured by the instrument between 300 and 380 nm. Seftor et al (2014) documented many aspects of the previous version of the data set that remain the same, but a number of changes for the V2 data set do reflect advances in the characterization of the NM sensor (Seftor and Jaross, 2017), which are relevant to this study. These are summarized as follows: (1) recalculation of instrument band-pass functions in the 300-310 nm region affected by the dichroic element of the nadir instrument, (2) improved wavelength registration, (3) an update to the instrument radiance calibration and (4) improvement to the stray-light correction.…”

Evaluating the Height of Biomass Burning Smoke Aerosols Retrieved from Synergistic Use of Multiple Satellite Sensors over Southeast Asia

“…For UVAI, the 340-378 nm wavelength pair of OMPS measurements, which is not affected by ozone absorption, is used and provides data at a spatial resolution of 50 × 50 km at nadir (Seftor et al, 2014). The VIIRS data are aggregated to match the OMPS resolution in the retrieval process, and the retrieved values are provided at the OMPS spatial resolution with a swath of 2800 km.…”