Calibrated spectral radiances in the near-infrared O2 and CO2 absorption bands, intended for retrievals of atmospheric column CO2 concentrations, at the highest spatial resolution ever acquired by a satellite instrument, are now available to the public from the National Aeronautics and Space Administration (NASA) Goddard Earth Sciences Data and Information Services Center (GES DISC), located in Greenbelt, Maryland. The data are provided to the GES DISC for archive and distribution by the Orbiting Carbon Observatory-2 (OCO-2) mission. OCO-2 mission operations and data processing take place at the Jet Propulsion Laboratory (JPL) in Pasadena, California.
OCO-2 was launched on a Delta II vehicle at 2:56 a.m. PDT (5:56 a.m. EDT) on Wednesday, July 2, 2014, from Vandenberg Air Force Base in California. OCO-2 incorporates three high-resolution spectrometers that make coincident measurements of reflected sunlight in the near-infrared CO2 absorption bands near 1.61 and 2.06 μm, and in molecular oxygen (O2) A-Band at 0.76 μm
Following the “checkout” phase of the mission, OCO-2 began its scientific observation phase. An image released at the recent American Geophysical Union 2014 Fall Meeting by the OCO-2 mission team showed preliminary retrieval of atmospheric CO2 concentrations, using the acquired radiances, over the period October 1 – November 11, 2014 (Figure 1).
OCO-2 has also been maneuvered into position to lead the “A-Train” constellation of Earth-observing satellites, which provides complementary Earth observations acquired nearly simultaneously by several different instruments (Figure 2). OCO-2 and the A-Train complete one Earth orbit every 99 minutes.
Figure 1. Preliminary CO2 global concentrations (volume mixing ratios, in parts per million) , retrieved from OCO-2 calibrated radiances, for the period October 1 – November 11, 2014. Elevated CO2 concentrations are evident over South America, southern Africa, China, and Indonesia. The limits on OCO-2 observations to the north and south are imposed by the required Sun angle for data acquisition. (Click on the image to view it full-size.)
Figure 2. OCO-2 leads the “A-Train” satellite constellation and is followed by the Japanese Aerospace Exploration Agency (JAXA) GCOM-W1 satellite and the NASA Aqua, Calipso, CloudSat, and Aura satellites. The Parasol satellite no longer orbits in the A-Train, due to depletion of maneuvering propellant. (Click on the image to view it full-size.)
This announcement marks the OCO-2 Project release of the Level 1B calibrated radiance spectra. The release of the full-physics Level 2 retrieval of column CO2 concentrations is expected in March 2015 and will represent a unique and major addition to NASA’s collections of satellite observations of atmospheric CO2. Mid-tropospheric CO2 concentrations from the Atmospheric Infrared Sounder (AIRS) sensor have been available since 2002, and reveal a previously unknown belt of elevated CO2 concentrations locked with the southern hemisphere mid-latitude jet stream (Figure 3). With OCO-2 and AIRS data at hand, researchers will have an unprecedented view of CO2 sources and sinks at the surface, as well as the transport and accumulations at different levels in the atmosphere.
Figure 3. AIRS mid-tropospheric CO2 volume mixing ratios (in part per million) for the month of October, 2014. (Click on the image to view it full-size.)
Data Release Information
This public release of OCO-2 data encompasses the radiometrically calibrated spectra (Level 1B), as well as upstream digital records (Level 1A; Attitude and Ephemeris of the spacecraft), which are used in the production of the Level 1B calibrated radiances.
- Documentation on the currently released products can be found at
- Product pages summarizing the essential details, including data access methods, are available from
- Users can directly download data from anonymous ftp at
For More Information About OCO-2
Users are encouraged to visit the OCO-2 Project Web site at JPL, http://oco.jpl.nasa.gov/, for detailed information on the technical specifications and principles of operation of the OCO-2 spacecraft and sensor. The Web site also provides information on the physical basis of the CO2 data retrievals using the short infrared spectra acquired by the spacecraft.