OMPS

OMPS
Name	OMPS
Type	Nadir and Limb Spectrometer
Operator	National Aeronautics and Space Administration / NOAA
Launched	Suomi NPP (2011), NOAA-20 (2017)
Applications	Atmospheric composition, ozone monitoring, aerosol detection
Wavelength	Ultraviolet-visible
Orbit	Low Earth orbit

OMPS presents a suite of satellite instruments designed to monitor stratospheric and tropospheric composition from orbit. Developed as a successor to earlier ultraviolet sounders, OMPS provides global observations of ozone, aerosols, and trace gases that support operational monitoring and scientific research. The instrument suite builds on heritage from sensors flown on platforms such as Total Ozone Mapping Spectrometer, Ozone Monitoring Instrument, and Solar Backscatter Ultraviolet Radiometer.

Overview

OMPS comprises complementary sensors that sample sunlight scattered by Earth's atmosphere and surface in the ultraviolet and visible bands. The program was implemented to continue long-term records initiated by missions including Nimbus-7, ERS-2, and MetOp series, and to serve operational agencies like National Oceanic and Atmospheric Administration and research centers such as Goddard Space Flight Center. Its measurements contribute to international assessments from bodies like the World Meteorological Organization and the United Nations Environment Programme.

Instrument Design and Components

The OMPS suite includes nadir and limb viewing units that use diffraction gratings, CCD detectors, and stray-light reduction optics. The Nadir Mapper and Nadir Profiler employ a pushbroom approach combined with slit spectrometers analogous to designs on Ozone Mapping and Profiler Suite and GOME-2 instruments. A Limb Profiler uses occultation and limb-scanning geometries similar to SBUV and SCIAMACHY concepts to retrieve vertical profiles. Mechanical and thermal subsystems were built to interface with spacecraft buses such as Suomi NPP and JPSS platforms, and to meet requirements driven by agencies including NOAA and NASA.

Data Products and Processing

OMPS delivers calibrated radiances, total column ozone, ozone profile retrievals, aerosol index products, and surface UV estimates. Processing pipelines adapted heritage algorithms from TOMS and OMI while integrating radiative transfer solvers used by research groups at Jet Propulsion Laboratory and Harvard-Smithsonian Center for Astrophysics. Level 0 telemetry is converted to Level 1B radiances, then to Level 2 geophysical retrievals using inversion techniques employed in studies from Rutgers University and University of Maryland. Data are archived in centers operated by National Centers for Environmental Information and disseminated to programs such as Global Ozone Monitoring Experiment archives.

Calibration and Validation

On-orbit calibration schemes for OMPS combine solar diffuser observations, lunar views, and vicarious calibration using well-characterized targets like Sahara Desert sites and Antarctic snowfields. Intercomparisons with instruments including OMI, GOME-2, and ground-based networks such as Network for the Detection of Atmospheric Composition Change are essential for long-term stability. Validation campaigns have involved airborne sensors from NASA ER-2, ozonesonde launches coordinated with World Ozone and Ultraviolet Radiation Data Centre, and balloon missions supported by institutions like NOAA ESRL. The calibration strategy leverages cross-calibration with TROPOMI and comparisons against modeled radiative transfer fields from groups at NCAR.

Missions and Operational History

OMPS instruments first flew on the Suomi NPP spacecraft in 2011 and were subsequently deployed on NOAA-20 as part of the Joint Polar Satellite System series. The flight history includes routine global mapping, targeted observations during events cataloged by Intergovernmental Panel on Climate Change reports, and responses to stratospheric disturbances noted after volcanic eruptions such as Eyjafjallajökull and Mount Pinatubo legacy analyses. Operational control and data distribution have involved partnerships between NASA, NOAA, and international collaborators at institutions like European Space Agency and Japan Aerospace Exploration Agency.

Scientific Applications and Discoveries

OMPS data have been used to monitor ozone hole dynamics over Antarctica and seasonal ozone variations linked to polar vortex changes studied by research teams at University of Cambridge and Massachusetts Institute of Technology. Studies combining OMPS with satellite records from Aqua, Aura, and Envisat have improved understanding of ozone recovery trends associated with the Montreal Protocol controls. OMPS aerosol index products have supported analyses of transcontinental dust transport from regions such as the Sahara Desert and Gobi Desert, and have contributed to air quality assessments tied to wildfire plumes documented for events like the Australian bushfires and California wildfires. Trace gas retrievals from OMPS have augmented monitoring efforts for halogenated compounds traced in inventories maintained by United Nations Environment Programme.

Limitations and Future Developments

OMPS faces limitations in vertical resolution for lower tropospheric ozone, sensitivity under cloudy scenes, and degradation due to stray light and detector aging observed in heritage sensors such as TOMS. Future developments aim to improve spectral resolution, revisit times, and limb-nadir synergistic retrievals through proposed instruments on follow-on platforms in the JPSS architecture and cooperative missions with ESA and JAXA. Advances in retrieval algorithms from groups at University of Oxford and California Institute of Technology and assimilation efforts in operational centers like European Centre for Medium-Range Weather Forecasts seek to extend OMPS utility for climate and air quality applications.

Category:Satellite sensors