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Full catalog/OCO3_L2_CO2Prior
OCO3_L2_CO2Prior·v11r·dataset

Best-guess CO₂ before measurement, monthly (OCO-3)

OCO-3 Level 2 CO2 prior based on CO2 monthly flask record, global meteorology, and age of air, Retrospective Processing V11r (OCO3_L2_CO2Prior) at GES DISC
atmosphere NASA GES_DISC Level 2 active
In plain English

What it measures. A best-guess starting estimate of how much carbon dioxide is in the air, worked out before the satellite's own measurement is applied. It draws on the long-term monthly CO2 record, global weather data, and how old the air is.

How it's made. Generated as part of the OCO-3 carbon-monitoring instrument's processing chain aboard the International Space Station; this is a calculated input rather than a direct measurement.

How & where you'd use it. A behind-the-scenes building block that the OCO-3 retrieval uses as its initial guess; most people would encounter it through the final CO2 products rather than using it directly.

What's measured

ATMOSPHERE › ATMOSPHERIC CHEMISTRY › CARBON AND HYDROCARBON COMPOUNDS › ATMOSPHERIC CARBON DIOXIDE

Coverage & cadence

  • Time span2019-08-06 → ongoing
  • Measured byISS (OCO-3)
  • Processing levelLevel 2
  • Spatial extent-180, -90, 180, 90
  • StatusACTIVE

What you can do with it

  • Map air pollutants — NO₂, aerosols, ozone
  • Track greenhouse gases and Earth's energy budget
  • Feed weather and air-quality analysis
Official description

Version 11r is the current version of the data set. Older versions will no longer be available and are superseded by Version 11r. The Orbiting Carbon Observatory -3 (OCO-3) was deployed to the International Space Station in May, 2019. It is technically a single instrument, almost identical to OCO-2. The Orbiting Carbon Observatory is the first NASA mission designed to collect space-based measurements of atmospheric carbon dioxide with the precision, resolution, and coverage needed to characterize the processes controlling its buildup in the atmosphere. OCO-3 incorporates three high-resolution spectrometers that make coincident measurements of reflected sunlight in the near-infrared CO2 near 1.61 and 2.06 micrometers and in molecular oxygen (O2) A-Band at 0.76 micrometers. The three spectrometers have different characteristics and are calibrated independently. Oxygen-A Band cloud screening algorithm is one of the primary cloud screening tools implemented in the operational OCO processing pipeline. The algorithm was introduced and applied to early GOSAT data with further analysis performed on OCO-2 simulations. The OCO ABO2 algorithm employs a fast Bayesian retrieval to estimate surface pressure and surface albedo from high resolution spectra of the molecular oxygen (O2) A-band, near 0.765 µm. The radiative transfer forward model (FM) assumes a clear-sky condition, i.e. Rayleigh scattering only, such that differences between the modeled and measured radiances are apparent when the measurement scene contains cloud or aerosol.

Get the data

oco3_l2_co2prior_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="OCO3_L2_CO2Prior",
    version="11r",
    bounding_box=(-122.5, 37.2, -121.8, 37.9),  # your area (W,S,E,N)
    temporal=("2024-01-01", "2024-12-31"),       # your dates
)
files = earthaccess.open(results)   # stream straight from GES_DISC
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.