The The OOrbiting rbiting CCarbon arbon OObservatory bservatory (OCO) Mission(OCO) Mission

Watching Earth Breathe…Mapping Carbon Dioxide Watching Earth Breathe…Mapping Carbon Dioxide from Spacefrom Space

Science Writers’ Workshop

American Geophysical Union Fall Meeting 2008

125

Carbon Dioxide is IncreasingCarbon Dioxide is Increasing

Carbon “Sinks” Vary from Year to Year: Carbon “Sinks” Vary from Year to Year: Why?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 Carbon Dioxide is Part of the Global Carbon CycleGlobal Carbon Cycle

About half the CO2 released by humans is absorbed by the ocean and land

Humans

Atmosphere

775 + 4/yr

Ocean

38,000

Land

2,000

~90

~120

~1208 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?Where Has All the Carbon Gone?

• Into the oceanocean– 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 landland– 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 We Measure Air to Understand Sources and SinksSinks

Air Parcel Air Parcel

Air Parcel

Sources Sinks

transport transport

Sample Sample

Changes in CO2 in the air contain information about all sources and sinks encountered along the way

Sources & Sinks Change COSources & Sinks Change CO2 2 in Space and in Space and Time Time

SiB-PCTM Simulation

Simulation and Animation Courtesy of Nick Parazoo, CSU

NASA’s Orbiting Carbon Observatory (OCO) Mission

NASA’s Orbiting Carbon Observatory NASA’s Orbiting Carbon Observatory Mission Will Measure Carbon Dioxide Mission Will Measure Carbon Dioxide

Over the GlobeOver 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%)

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 The OCO Instrument Will Make Precise Carbon Dioxide Measurements from Carbon Dioxide Measurements from

SpaceSpace

Collimator

Slit

Grating

RelayOptics Telescope

Detector

Camera

O2 A-Band

CO2 1.61m Band

CO2 2.06 m Band

Grating

Telescope

Remote Electronics

ThermalRadiator

RelayOptics

The OCO instrument uses three high-resolution grating spectrometers to measure the absorption of reflected sunlight by

CO2 and oxygen

Instrument + Spacecraft Bus = Instrument + Spacecraft Bus = Observatory Observatory

Next Steps: Launch Vehicle Next Steps: Launch Vehicle Integration Integration

• Launch Site: - VAFB, Calif. (Site 576E)

Orbital Sciences Corporation Taurus 3110

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

OCO Will Fly in the Earth Observing OCO Will Fly in the Earth Observing System Afternoon Constellation (A-System Afternoon Constellation (A-

Train)Train)

OCO flies at the head of the A-Train, three minutes ahead of Aqua• 705-kilometer altitude, sun-synchronous, 98.2inclination, 98.8- minute period • Global coverage with a 16-day (233-orbit) ground track repeat cycle

Coordinated Observations

What Are the Benefits of an Improved What Are the Benefits of an Improved Understanding of the Role of COUnderstanding of the Role of CO22 in the in the

Carbon Cycle and Climate?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 30

0 pp

m!

Carbon Sinks Make Future COCarbon Sinks Make Future CO22 UncertainUncertain

Friedlingstein et al (2006)

Carbon Sinks Are a CommodityCarbon Sinks Are a Commodity

OCO is Part of an International EffortOCO 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

SummarySummary

• 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