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NASA’s OCO mission aims to measure carbon dioxide globally to understand its sources and sinks, aiding climate research. Launching in 2009, it will provide crucial data for climate modeling and analyzing carbon cycle processes.
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The Orbiting Carbon Observatory (OCO) MissionWatching Earth Breathe…Mapping Carbon Dioxide from Space Science Writers’ Workshop American Geophysical Union Fall Meeting 2008
Carbon “Sinks” Vary from Year to Year: Why? Half the CO2 “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 Atmosphere Ocean 775 + 4/yr 38,000 This “missing” carbon is hard to find among large natural fluxes About half the CO2 released by humans is absorbed by the ocean and land ~120 ~90 ~120 ~90 8 GtC/yr Land Humans 2,000 GtC/yr: billions of tons of carbon per year
Where Has All the Carbon Gone? • Into the ocean • Solubility pump (CO2 very soluble in cold water, but rates are limited by slow physical mixing) • Biological pump (slow “rain” of organic debris) • Into the land • CO2 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 transport transport Sinks Air Parcel Air Parcel Sources Sample Sample Changes in CO2 in the air contain information about all sources and sinks encountered along the way
Sources & Sinks Change CO2 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 CO2 mixing ratio over the sunlit hemisphere • Collect spectra of CO2 and O2 absorption in reflected sunlight over the globe • Validate measurements to ensure CO2 accuracy of 1 - 2 ppm (0.3 - 0.5%) Initial Surface and Atmospheric State OCO/AIRS/GOSAT Generate Synthetic Spectrum Compare to Observed Spectrum FTS Tower Retrieve New Atmospheric State Aircraft Flask CO2
The OCO Instrument Will Make Precise Carbon Dioxide Measurements from Space Relay Optics Relay Optics Telescope Detector Slit Telescope O2 A-Band Collimator CO2 1.61m Band Camera CO2 2.06 m Band Thermal Radiator Grating Remote Electronics Grating The OCO instrument uses three high-resolution grating spectrometers to measure the absorption of reflected sunlight by CO2 and oxygen
Next Steps: Launch Vehicle Integration Orbital Sciences Corporation Taurus 3110 • Launch Site: • - VAFB, Calif. (Site 576E)
OCO Measures Carbon Dioxide Over the Entire Sunlit Hemisphere Every 16 Days
OCO Will Fly in the Earth Observing System Afternoon Constellation (A-Train) Coordinated Observations • OCO flies at the head of the A-Train, three minutes ahead of Aqua • 705-kilometer altitude, sun-synchronous, 98.2 degrees inclination, 98.8- minute period • Global coverage with a 16-day (233-orbit) ground track repeat cycle
What Are the Benefits of an Improved Understanding of the Role of CO2 in the Carbon Cycle and Climate?
Carbon Sinks Make Future CO2 Uncertain Land 300 ppm! Atmosphere Ocean • Coupled global models of climate and the land & ocean carbon cycle • Given nearly identical human emissions, different models project dramatically different futures! Friedlingstein et al (2006)
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 CO2 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 CO2 measurements from other missions • Upper tropospheric CO2 from Aqua AIRS • Column CO2 from the ESA EnviSat SCIAMACHY and the JAXA GOSAT missions NOAA ESRL DoE ARM & TCCON EOS Aqua AIRS JAXA GOSAT
Summary • Improved CO2 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 CO2 with the accuracy and coverage needed to identify and characterize CO2 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 • CO2 retrievals: <12 months after launch