Articles | Volume 10, issue 2
Research article
15 Feb 2017
Research article |  | 15 Feb 2017

The Orbiting Carbon Observatory-2: first 18 months of science data products

Annmarie Eldering, Chris W. O'Dell, Paul O. Wennberg, David Crisp, Michael R. Gunson, Camille Viatte, Charles Avis, Amy Braverman, Rebecca Castano, Albert Chang, Lars Chapsky, Cecilia Cheng, Brian Connor, Lan Dang, Gary Doran, Brendan Fisher, Christian Frankenberg, Dejian Fu, Robert Granat, Jonathan Hobbs, Richard A. M. Lee, Lukas Mandrake, James McDuffie, Charles E. Miller, Vicky Myers, Vijay Natraj, Denis O'Brien, Gregory B. Osterman, Fabiano Oyafuso, Vivienne H. Payne, Harold R. Pollock, Igor Polonsky, Coleen M. Roehl, Robert Rosenberg, Florian Schwandner, Mike Smyth, Vivian Tang, Thomas E. Taylor, Cathy To, Debra Wunch, and Jan Yoshimizu

Abstract. The Orbiting Carbon Observatory-2 (OCO-2) is the first National Aeronautics and Space Administration (NASA) satellite designed to measure atmospheric carbon dioxide (CO2) with the accuracy, resolution, and coverage needed to quantify CO2 fluxes (sources and sinks) on regional scales. OCO-2 was successfully launched on 2 July 2014 and has gathered more than 2 years of observations. The v7/v7r operational data products from September 2014 to January 2016 are discussed here. On monthly timescales, 7 to 12 % of these measurements are sufficiently cloud and aerosol free to yield estimates of the column-averaged atmospheric CO2 dry air mole fraction, XCO2, that pass all quality tests. During the first year of operations, the observing strategy, instrument calibration, and retrieval algorithm were optimized to improve both the data yield and the accuracy of the products. With these changes, global maps of XCO2 derived from the OCO-2 data are revealing some of the most robust features of the atmospheric carbon cycle. This includes XCO2 enhancements co-located with intense fossil fuel emissions in eastern US and eastern China, which are most obvious between October and December, when the north–south XCO2 gradient is small. Enhanced XCO2 coincident with biomass burning in the Amazon, central Africa, and Indonesia is also evident in this season. In May and June, when the north–south XCO2 gradient is largest, these sources are less apparent in global maps. During this part of the year, OCO-2 maps show a more than 10 ppm reduction in XCO2 across the Northern Hemisphere, as photosynthesis by the land biosphere rapidly absorbs CO2. As the carbon cycle science community continues to analyze these OCO-2 data, information on regional-scale sources (emitters) and sinks (absorbers) which impart XCO2 changes on the order of 1 ppm, as well as far more subtle features, will emerge from this high-resolution global dataset.

Short summary
This paper describes the measurements of atmospheric carbon dioxide collected in the first 18 months of the satellite mission known as the Orbiting Carbon Observatory-2 (OCO-2). The paper shows maps of the carbon dioxide data, data density, and other data fields that illustrate the data quality. This mission has collected a more precise, more dense dataset of carbon dioxide then we have ever had previously.