TEMPO Mission Releases Beta Level 1, 2, and 3 Version 03 Data Products

NASA's Atmospheric Science Data Center (ASDC) released a new suite of beta Level 1, 2, and 3 Version 03 data products from the Tropospheric Emissions: Monitoring of Pollution (TEMPO) mission. An earlier suite of beta Level 1 data products was released in February 2024.

The TEMPO instrument is an ultraviolet and visible spectrometer that was built by Ball Aerospace (now known as BAE Systems, Inc., Space & Mission Systems) and launched into space on April 7, 2023, aboard the Intelsat 40e satellite built by Maxar Technologies. TEMPO is on the Earth-facing side of the satellite, which is in a geostationary orbit 22,000 miles above Earth's equator at 91°W. This allows the instrument to maintain a constant view of North America so that its light-collecting mirror can make a complete east to west scan of its field of regard (FOR)—from the Atlantic to the Pacific, and from the Yucatan Peninsula to the Canadian oil sands—during daylight hours. By measuring sunlight reflected and scattered from Earth's surface and atmosphere back to the instrument's detectors, TEMPO's ultraviolet (UV) and visible light sensors provide spectra of ozone (O₃), nitrogen dioxide (NO₂), formaldehyde (HCHO), and other elements of daily atmospheric chemistry cycles.

Version 03 Data Products

• TEMPO Level 1 Dark Exposure, Version 03 (TEMPO_DRK_L1) BETA Provides the processed dark currents, corresponding to either solar irradiance measurements or radiance measurements. Each file includes the measured dark currents for all the North-South cross-track pixels. The files contain information on dark current rates of all frames and their average for the UV and visible bands, pixel quality flags, and other ancillary information.
• TEMPO Level 1 Solar Irradiance, Version 03 (TEMPO_IRR_L1) BETA Provides solar irradiance measured using the working solar diffuser. Each file includes the measured solar irradiance for all the North-South cross-track pixels. The files contain information on radiometrically- and wavelength-calibrated solar irradiance for the UV and visible bands, corresponding noise, parameterized wavelength grid, solar viewing geometry, quality flags, and other ancillary information.
• TEMPO Level 1 Solar Irradiance (Reference Diffuser), Version 03 (TEMPO_IRRR_L1) BETA Provides solar irradiance measured using the reference solar diffuser. Each file includes the measured solar irradiance for all the North-South cross-track pixels. The files contain information on radiometrically- and wavelength-calibrated solar irradiance for the UV and visible bands, corresponding noise, parameterized wavelength grid, solar viewing geometry, quality flags, and other ancillary information.
• TEMPO Level 1 Geolocated Earth Radiances, Version 03 (TEMPO_RAD_L1) BETA Provides radiance information at TEMPO's native spatial resolution (~10 km² at the center of the FOR) for individual granules. Each granule covers the entire North-South TEMPO FOR but only a portion of the East-West FOR. The files contain information on radiometrically- and wavelength-calibrated and geolocated radiances for the UV and visible bands, corresponding noise, parameterized wavelength grid, geolocation, viewing geometry, quality flags, and other ancillary information.
• TEMPO Level 1 Geolocated Earth Radiances Twilight, Version 03 (TEMPO_RADT_L1) BETA Provides radiance measured during twilight hours to capture city lights at TEMPO's native spatial resolution for individual granules. Each granule covers the entire North-South TEMPO FOR but only a portion of the East-West FOR. The files contain information on radiometrically-calibrated and geolocated radiances for the UV and visible bands, corresponding noise, parameterized wavelength grid, geolocation, viewing geometry, quality flags, and other ancillary information.
• TEMPO Level 2 Cloud Pressure and Fraction (O2-O2 Dimer), Version 03 (TEMPO_CLDO4_L2) BETA Provides cloud information at TEMPO's native spatial resolution for individual granules. Each granule covers the entire North-South TEMPO FOR but only a portion of the East-West FOR. The files contain information on effective cloud fraction (ECF), cloud optical centroid pressure (OCP), processing quality flags, and other ancillary information.
• TEMPO Level 2 Formaldehyde Total Column, Version 03 (TEMPO_HCHO_L2) BETA Provides trace gas information at TEMPO's native spatial resolution for individual granules. Each granule covers the entire North-South TEMPO FOR but only a portion of the East-West FOR. The files contain information on vertical columns, ancillary data used in air mass factor calculations and reference sector corrections, and retrieval quality flags.
• TEMPO Level 2 NO₂ Tropospheric and Stratospheric Columns, Version 03 (TEMPO_NO2_L2) BETA Provides trace gas information at TEMPO's native spatial resolution for individual granules. Each granule covers the entire North-South TEMPO FOR but only a portion of the East-West FOR. The files contain information on tropospheric, stratospheric and total NO₂ vertical columns, ancillary data used in air mass factor and stratospheric/tropospheric separation calculations, and retrieval quality flags.
• TEMPO Level 2 Ozone Total Column, Version 03 (TEMPO_O3TOT_L2) BETA Provides ozone information at TEMPO’s native spatial resolution for individual granules. Each granule covers the entire North-South TEMPO FOR but only a portion of the East-West FOR. The files contain information on total column ozone and some auxiliary derived and ancillary input parameters including N-values, effective Lambertian scene-reflectivity, UV aerosol index, sulfur dioxide (SO₂) index, effective cloud fraction, effective cloud pressure, radiative cloud fraction, ozone below clouds, terrain height, geolocation, solar and satellite viewing angles, and quality flags.
• TEMPO Level 3 Gridded Cloud Fraction and Pressure (O2-O2 Dimer), Version 03 (TEMPO_CLDO4_L3) BETA Provides cloud information on a regular grid covering the TEMPO FOR for nominal TEMPO observations. Level 3 files are derived by combining information from all Level 2 files constituting a TEMPO East-West scan cycle. The files contain information on effective cloud fraction, cloud optical centroid pressure, and ancillary data.
• TEMPO Level 3 Gridded Formaldehyde Total Column, Version 03 (TEMPO_HCHO_L3) BETA Provides trace gas information on a regular grid covering the TEMPO FOR for nominal TEMPO observations. Level 3 files are derived by combining information from all Level 2 files constituting a TEMPO East-West scan cycle. The files contain information on formaldehyde vertical columns, ancillary data used in air mass factor calculations and reference sector or de-striping corrections, and retrieval quality flags.
• TEMPO Level 3 Gridded NO₂ Tropospheric and Stratospheric Columns, Version 03 (TEMPO_NO2_L3) BETA Provides trace gas information on a regular grid covering the TEMPO field of regard for nominal TEMPO observations. Level 3 files are derived by combining information from all Level 2 files constituting a TEMPO East-West scan cycle. The files contain information on tropospheric, stratospheric and total NO₂ vertical columns, ancillary data used in air mass factor and stratospheric/tropospheric separation calculations, and retrieval quality flags.
• TEMPO Level 3 Gridded Ozone Total Column, Version 03 (TEMPO_O3TOT_L3) BETA Provides ozone information on a regular grid covering the TEMPO field of regard for nominal TEMPO observations. Level 3 files are derived by combining information from all Level 2 files constituting a TEMPO East-West scan cycle. The files contain information on total column ozone and some auxiliary derived and ancillary input parameters including effective cloud fraction, effective cloud pressure, radiative cloud fraction, SO₂ index, and terrain pressure.

All of these data products are provided in netCDF4 format and remain at a beta maturity level, which means the products are minimally validated and may contain errors. Scientists from the Smithsonian Astrophysical Observatory (SAO), part of the Harvard & Smithsonian Center for Astrophysics, are currently in the process of validating the geophysical retrievals for ozone, nitrogen dioxide, formaldehyde, and clouds.

"These data products are still at the beta maturity level, per the Beta Product Maturity level defined in the TEMPO validation plan," said TEMPO Principal Investigator (PI) Dr. Xiong Liu. "The maturity level of data products will be updated once a more careful validation and assessment determines that they have reached a higher level of maturity."

Liu expects it will be several months before the beta level data products are identified as provisional. Until then, he cautioned that the beta products should not be used operationally, as unknown anomalies may still exist. "These beta TEMPO products should not be used in publications and users should refrain from making conclusive public statements regarding science and applications of the TEMPO data products until they are designated to be at the provisional validation status," he said.

In addition to releasing these datasets, NASA's ASDC has made (or in some instances will make) a variety of tools and services available so users can access and work with these data. The table below identifies the tools and services that support TEMPO data by data processing level.

According to Liu, this release of TEMPO version 03 products will enable those eager to enlist TEMPO data in their work to begin using real TEMPO data products.

"More than 600 early adopters (or application users), including federal, state, and local air quality agencies; public health workers; educators; non-profit organizations; and international partners have been trained with proxy TEMPO data before launch and are waiting to learn how to use TEMPO data for societal benefit," Liu said. "Now they have TEMPO data products to use in developing their applications."

The TEMPO Early Adopters program was established in 2019 to facilitate interactions between the TEMPO science team and the community of stakeholders and end users. The program's goal is to understand and demonstrate the capabilities and applications of TEMPO data before the instrument launched to accelerate use of the mission's data products. A key component of the program was the generation and dissemination of TEMPO proxy data for use and analysis by Early Adopter program participants. These pre-launch activities informed users on the impact of TEMPO data in their research and operations, identified advantages and limitations of the proxy data, and provided feedback to the TEMPO science team for understanding how the official TEMPO products could be tailored to better meet users' needs.

This release of beta Level 2 and 3 Version 03 data products (along with Version 03 of the previously-released beta Level 1 data products) marks something of a milestone for the mission, as it portends the availability of the TEMPO data record from first light to the present.

"This is our first official public release of Version 03 Level 2 and 3 data products, and it is a big deal," said Liu. "Going forward, these data products will be available to everyone approximately six hours after observation. For measurements taken before the release, we will process them in parallel starting from our first light data in August 2023. In about three months or so, we will have the entire TEMPO data record processed consistently with the same science algorithms."

For ASDC Science Lead Dr. Hazem Mahmoud, the release of these datasets is critical for a variety of remote sensing applications.

"These Level 2 and Level 3 data are crucial for understanding our dynamically changing planet and will contribute to environmental studies, climate research, disaster monitoring, and various applications requiring a deeper understanding of specific geophysical properties," Mahmoud said.

About NASA's ASDC

ASDC is located within the Science Directorate at NASA's Langley Research Center in Hampton, VA. This NASA Distributed Active Archive Center (DAAC) manages, archives, and distributes data related to radiation budget, clouds, aerosols, and tropospheric composition that are part of NASA's Earth Observing System Data and Information System (EOSDIS) collection and provides tools and applications for working with these data. These data are important for understanding the causes and processes of global climate change and the consequences of human activities on Earth's atmosphere and climate.

Data Access and Learning Resources

Users can access this suite of TEMPO Version 03 data using NASA’s Earthdata Search or through the ASDC website.

Users may learn more about TEMPO data and data services through the ASDC TEMPO StoryMap and access the TEMPO NO2 troposphere ArcGIS Image service.