Space Based Measurements of Atmospheric Carbon Dioxide with the NASA Orbiting Carbon Observatory

David Crisp, Jet Propulsion Laboratory, California Institute of Technology, david.crisp@jpl.nasa.gov (Presenting)

The Orbiting Carbon Observatory (OCO) is the first NASA satellite designed to measure atmospheric carbon dioxide (CO₂) with the precision and sampling needed to identify and quantify regional scale CO₂ sources and sinks. The Observatory carries a single instrument that uses high resolution grating spectrometers to measure reflected sunlight in the CO₂ bands at 1.61 and 2.06 microns and in the molecular oxygen (O₂) A-band at 0.765 microns. OCO is on schedule for a December 15, 2008 launch readiness date. It is expected to begin routinely returning CO₂ and O₂ spectra about 45 days after launch. Within six months of that date, calibrated, geolocated spectral radiances will start to be archived in the JPL Distributed Active Archive Center. An additional 3 months will be needed to retrieve, validate, and begin archiving estimates of the column-averaged CO₂ dry air mole fraction, X_CO2.

The pre-launch instrument qualification and calibration tests were completed in early March of 2008. As part of this testing program, the end-to-end performance of the flight instrument was verified by recording atmospheric CO₂ and O₂ spectra and comparing these results to spectra recorded simultaneously from a collocated ground-based high-resolution Fourier transform spectrometer that will be used as part of the OCO ground validation program. These tests indicate that the instrument meets its design objectives and will provide excellent data for X_CO2 retrievals.