The Orbiting Carbon Observatory (OCO) Mission Watching Earth Breathe…Mapping Carbon Dioxide from Space Science Writers’ Workshop American Geophysical Union Fall Meeting 2008

125 Carbon Dioxide is Increasing

Carbon “Sinks” Vary from Year to Year: Why? Half the CO 2 “goes away!” Some years almost all the fossil carbon goes into the atmosphere, some years almost none Year-to-year variability in sink activity is much greater than in fossil fuel emissions

Carbon Dioxide is Part of the Global Carbon Cycle About half the CO 2 released by humans is absorbed by the ocean and land Humans Atmosphere /yr Ocean 38,000 Land 2,000 ~90 ~120 8 GtC/yr ~90 This “missing” carbon is hard to find among large natural fluxes GtC/yr: billions of tons of carbon per year

Where Has All the Carbon Gone? oceanInto the ocean –Solubility pump (CO 2 very soluble in cold water, but rates are limited by slow physical mixing) –Biological pump (slow “rain” of organic debris) landInto the land –CO 2 fertilization (plants eat CO2 … is more better?) –Nutrient fertilization (nitrogen deposition and fertilizers) –Land-use change (forest regrowth, fire suppression, woody encroachment) –Response to changing climate (e.g., high-latitude warming)

We Measure Air to Understand Sources and Sinks Air Parcel Sources Sinks transport Sample Changes in CO 2 in the air contain information about all sources and sinks encountered along the way

Sources & Sinks Change CO 2 in Space and Time SiB-PCTM Simulation Simulation and Animation Courtesy of Nick Parazoo, CSU

NASA’s Orbiting Carbon Observatory (OCO) Mission

NASA’s Orbiting Carbon Observatory Mission Will Measure Carbon Dioxide Over the Globe Retrieve variations in the column-averaged CO 2 mixing ratio over the sunlit hemisphere Collect spectra of CO 2 and O 2 absorption in reflected sunlight over the globe Validate measurements to ensure CO 2 accuracy of ppm ( %) Flask Aircraft FTS OCO/AIRS/GOSAT Tower Initial Surface and Atmospheric State Generate Synthetic Spectrum Compare to Observed Spectrum Retrieve New Atmospheric State CO2

The OCO Instrument Will Make Precise Carbon Dioxide Measurements from Space Collimator Slit Grating Relay Optics Telescope Detector Camera O 2 A-Band CO  m Band CO  m Band Grating Telescope Remote Electronics Thermal Radiator Relay Optics The OCO instrument uses three high-resolution grating spectrometers to measure the absorption of reflected sunlight by CO 2 and oxygen

Instrument + Spacecraft Bus = Observatory

Next Steps: Launch Vehicle Integration Launch Site: - VAFB, Calif. (Site 576E) Orbital Sciences Corporation Taurus 3110

OCO Measures Carbon Dioxide Over the Entire Sunlit Hemisphere Every 16 Days

OCO Will Fly in the Earth Observing System Afternoon Constellation (A-Train) OCO flies at the head of the A-Train, three minutes ahead of Aqua 705-kilometer altitude, sun-synchronous, 98.2  inclination, minute period Global coverage with a 16-day (233-orbit) ground track repeat cycle Coordinated Observations

What Are the Benefits of an Improved Understanding of the Role of CO 2 in the Carbon Cycle and Climate?

Coupled global models of climate and the land & ocean carbon cycle Given nearly identical human emissions, different models project dramatically different futures! Land Ocean Atmosphere 300 ppm! Carbon Sinks Make Future CO 2 Uncertain Friedlingstein et al (2006)

Carbon Sinks Are a Commodity

OCO is Part of an International Effort The OCO mission is working closely with: –National Oceanic and Atmospheric Administration’s Environmental Research Laboratory (NOAA ESRL), which operates the ground-based CO 2 monitoring network –Department of Energy Atmospheric Radiation Monitoring (DoE ARM) program, which hosts the OCO ground-based validation spectrometers –The Total Column Carbon Observing Network (TCCON), which deploys and manages the global network of ground-based spectrometers OCO measurements will be combined with CO 2 measurements from other missions –Upper tropospheric CO 2 from Aqua AIRS –Column CO 2 from the ESA EnviSat SCIAMACHY and the JAXA GOSAT missions NOAA ESRL DoE ARM & TCCON EOS Aqua AIRS JAXA GOSAT

Summary Improved CO 2 measurements are essential for understanding the processes controlling its current buildup, and eventual impact on our climate OCO is the first NASA satellite designed to measure atmospheric CO 2 with the accuracy and coverage needed to identify and characterize CO 2 sources and sinks on regional scales over the entire globe –Earliest launch date: January 30, 2009 –Launch site: Vandenberg Air Force Base, Calif. –0rbit: 705-km altitude, sun synchronous, 1:30 p.m. –Operating lifetime: at least two years –Data archiving schedule Calibrated, geolocated spectra: <9 months after launch CO 2 retrievals: <12 months after launch