Measuring atmospheric carbon dioxide from space with the Orbiting Carbon Observatory-2 (OCO-2)

The Orbiting Carbon Observatory-2 (OCO-2) is this first NASA satellite designed to measure atmospheric carbon dioxide (CO2) with the accuracy, resolution, and coverage needed to detect CO2 sources and sinks on regional scales over the globe. OCO-2 was launched from Vandenberg Air Force Base on 2 July 2014, and joined the 705 km Afternoon Constellation a month later. Its primary instrument, a 3-channel imaging grating spectrometer, was then cooled to its operating temperatures and began collecting about one million soundings over the sunlit hemisphere each day. As expected, about 13% of these measurements are sufficiently cloud free to yield full-column estimates of the columnaveraged atmospheric CO2 dry air mole fraction, XCO2. After almost a full year in orbit, the XCO2 product is beginning to reveal some of the most robust features of the atmospheric carbon cycle, including the northern hemisphere spring drawdown, and enhanced values co-located with intense fossil fuel and biomass burning emissions. As the carbon cycle science community continues to analyze these OCO-2 data, information on regional-scale sources (emitters) and sinks (absorbers) as well as far more subtle features are expected to emerge from this high resolution, global data set.