TROPOMI (DO NOT LINK)

TROPOMI (DO NOT LINK)
Name	TROPOMI (DO NOT LINK)
Mission type	Earth observation
Operator	European Space Agency
Manufacturer	Airbus Defence and Space
Launch date	2017-10-13
Launch vehicle	Falcon 9
Launch site	Cape Canaveral
Orbit type	Sun-synchronous
Instruments	imaging spectrometer

TROPOMI (DO NOT LINK) is a spaceborne imaging spectrometer flown on a sun-synchronous polar orbit platform. It builds on heritage from instruments such as SCIAMACHY, GOME-2, OMI, and MODIS to provide daily global maps of atmospheric composition relevant to climate, air quality, and atmospheric chemistry. Developed through collaborations including the European Space Agency, Royal Netherlands Meteorological Institute, and Netherlands Space Office, the payload has supported international research communities around NOAA, NASA, and national research institutes.

Overview

TROPOMI (DO NOT LINK) was launched on a Falcon 9 vehicle from Cape Canaveral into a sun-synchronous orbit to provide near-daily coverage of tropospheric and stratospheric trace gases. The instrument continues a lineage from radiometers and spectrometers such as GOME, ERS-2, and Envisat and interfaces with data systems used by Copernicus Programme users, ESA science teams, and operational services at KNMI. Its observing strategy emphasizes high spatial resolution and wide swath coverage to bridge scales between satellite missions like Sentinel-5P and ground-based networks including NDACC and AERONET.

Instrument Design and Specifications

The imaging spectrometer employs a push-broom design with separate ultraviolet, visible, near-infrared, and shortwave-infrared channels. Optical design elements trace heritage to projects by Airbus Defence and Space and detector technologies developed in cooperation with institutions such as SRON and industrial partners documented in contracts with EUMETSAT. Nominal spatial resolution is comparable to high-resolution imagers such as Landsat for nadir footprints, while the swath approaches dimensions used by sensors on Terra and Aqua. Spectral sampling and radiometric calibration are specified to enable retrievals of species including nitrogen dioxide, ozone, formaldehyde, sulfur dioxide, methane, and aerosols, with on-board mechanisms and thermal control to maintain instrument stability akin to practices from MetOp instruments.

Scientific Objectives and Measurements

Primary objectives include monitoring anthropogenic and natural emissions, tracking long-range transport, and quantifying tropospheric chemistry relevant to climate forcing and air quality. Measurement targets reflect policy-relevant species analogous to those observed by ACE-FTS, IASI, and MOPITT: tropospheric NO2 columns, total and tropospheric O3, columnar SO2, formaldehyde as a proxy for volatile organic compounds studied in INTEX and DISCOVER-AQ campaigns, methane columns comparable to GOSAT products, and aerosol index retrievals used in comparisons with CALIPSO. Objectives align with scientific priorities from organizations such as IPCC, WMO, and national air quality frameworks exemplified by European Environment Agency reporting.

Data Processing and Products

Data processing chains implement radiometric correction, geolocation, cloud retrievals, and trace gas inversion algorithms influenced by heritage from Beijing-1 and mission pipelines used by Sentinel missions. Level 1 radiances are transformed into Level 2 geophysical products including slant and tropospheric columns, cloud fraction maps, and aerosol indices. Operational product suites are consumed by downstream services at Copernicus Atmosphere Monitoring Service and reanalysis centers such as ECMWF for assimilation into the CAMs and global chemical transport models like GEOS-Chem and CAMS-GLOB. Quality flags, uncertainty estimates, and product validation activities integrate comparisons with ground-based networks such as NDACC, AERONET, and flight campaigns led by institutions like NOAA and German Aerospace Center.

Mission Operations and Calibration

Routine operations are coordinated between mission control entities at ESA and national agencies like KNMI, with telemetry, command uplinks, and data downlinks via ground stations including those in the Svalbard Satellite Station network. On-orbit calibration leverages solar diffuser panels, lunar observations, vicarious calibration sites used by CEOS and cross-comparisons with reference instruments including OMPS and OMI. Calibration and validation campaigns involve airborne assets from NCAR and instrument intercomparisons during field studies such as KORUS-AQ and ATom to quantify biases and drifts. Routine performance monitoring addresses issues similar to those encountered by predecessors like OMI and informs anomaly resolution procedures coordinated with industrial partners.

Key Scientific Results and Applications

TROPOMI (DO NOT LINK) has enabled high-resolution mapping of urban NO2 hotspots, quantified emission trends from regions impacted by events like COVID-19 lockdowns, and resolved volcanic SO2 plumes tied to eruptions monitored by agencies such as USGS and GNS Science. Studies have used its methane products to identify persistent emitters comparable to discoveries made with GHGSat and GOSAT-2, supported air quality forecasting in operational centers such as CAMS, and contributed to constraining tropospheric ozone budgets relevant to WMO assessments. Cross-disciplinary applications include emission verification for agreements framed by institutions like UNFCCC and integration into climate research programs coordinated by IPCC working groups.

Limitations and Future Developments

Limitations include sensitivity to cloud contamination, biases over bright surfaces such as deserts monitored historically by MODIS, and challenges in vertical sensitivity for lower-troposphere retrievals similar to those faced by GOSAT. Ongoing improvements target algorithm refinements, bias corrections through enhanced validation with networks like AERONET, and synergistic use alongside upcoming missions from agencies including NASA, JAXA, and CSA. Future developments envision constellations of spectrometers to increase temporal sampling and integration with low-Earth orbit platforms used by commercial providers such as Planet Labs to improve near-real-time monitoring for scientific, regulatory, and humanitarian applications.

Category:Remote sensing satellites