OCO-3: Space-Based Atmospheric CO2 Spectra from the ISS

NASA's Orbiting Carbon Observatory-3 (OCO-3) Level 1B dataset provides calibrated, geolocated science spectra from an instrument deployed to the International Space Station in May 2019. The data are collected by three high-resolution spectrometers measuring reflected sunlight at specific near-infrared and oxygen A-band wavelengths to infer atmospheric carbon dioxide. A primary use of the spectra is for the Oxygen-A Band cloud screening algorithm, which employs a fast Bayesian retrieval to estimate surface pressure and albedo and identify scenes containing cloud or aerosol.

Use Cases

• Estimating surface pressure and albedo based on high-resolution O2 A-band spectra using a Bayesian retrieval.
• Screening measurement scenes for cloud and aerosol contamination using the Oxygen-A Band algorithm.
• Analyzing spatial and temporal patterns of atmospheric carbon dioxide from a space-based platform.
• Validating and comparing carbon dioxide measurements with data from the similar OCO-2 satellite mission.

Strengths

• Data originates from a NASA mission specifically designed for precise, space-based measurement of atmospheric carbon dioxide.
• Incorporates three independently calibrated spectrometers for coincident measurements at multiple wavelengths.
• Represents the current Version 10r of retrospective processing, superseding all older versions.

Limitations

• Key metadata such as row count, file size, and specific column names are not provided in the available sources.
• Conflicting last-updated dates exist between platforms (2026-04-09 on Data.gov vs. 2023-11-12 on NASA Earthdata).
• The radiative transfer model assumes clear-sky conditions, which may limit direct use in heavily cloudy or aerosol-laden scenes without correction.

Provenance

Source

National Aeronautics and Space Administration (NASA)

Collection Method

Collected by the OCO-3 instrument's spectrometers aboard the International Space Station.

Time Range

Measurements began after deployment in May 2019; specific end date not provided.

Freshness

2026-04-09 (most recent update reported, though conflicting with another source)

Geography

Global coverage from the International Space Station's orbit.