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| Titel |
The Orbiting Carbon Observatory (OCO-2) Mission and ACOS |
| VerfasserIn |
Michael Gunson, Annmarie Eldering, David Crisp, Charles Miller |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250053722
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| Zusammenfassung |
| The NASA Orbiting Carbon Observatory (OCO-2) will make space-based measurements of
atmospheric CO2 with the precision, resolution, and coverage needed to characterize CO2
sources and sinks on regional scales and quantify their variability over the seasonal cycle.
After the failed launch of OCO, Congress instructed NASA to restart the OCO mission in the
2010 budget authorization. The OCO-2 mission will undergo review for authorization
to proceed in early October 2010, and could be ready for launch into the Earth
Observing System Afternoon Constellation (A-Train) in February 2013. The OCO-2
mission will be a ‘carbon copy’ of the OCO mission, to minimize schedule and cost
risks.
OCO-2 will carry a single instrument that incorporates 3 high resolution grating
spectrometers that will make bore-sighted measurements of reflected sunlight in near-infrared
CO2 and molecular oxygen (O2) absorption bands. These measurements will be combined to
provide spatially resolved estimates of the column-averaged CO2 dry air mole fraction,
XCO2. The instrument collects 12 to 24 XCO2 soundings/second over the sunlit portion of the
orbit, yielding 200 to 400 soundings per degree of latitude, or 7 to 14 million soundings every
16 days. Thick clouds and aerosols will reduce the number of soundings available for XCO2
retrievals by 80-90%, but the remaining data is expected to yield XCO2 estimates with
accuracies of ~0.3 to 0.5% (1 to 2 ppm) on regional scales every month. To verify the
accuracy of the space-based XCO2 data, the OCO-2 validation program will use
ground-based, solar-viewing Fourier Transform Spectrometers (FTS) in the Total
Carbon Column Observing Network (TCCON) to tie the space-based XCO2 with the
World Meteorological Organization (WMO) standard for atmospheric CO2, which is
based on in situ observations of CO2 from flask measurements, tall towers, and
aircraft.
In preparation for the OCO-2 mission, we are collaborating on the ACOS (Atmospheric
Carbon Observations from Space) project. In the ACOS project, we are retrieving XCO2
using the OCO-2 algorithm with the GOSAT measurements. We now have XCO2
measurements from the Spring of 2009 to present, and they are being validated with the
TCCON network.
This presentation will provide an overview of ACOS results and the OCO-2
mission, including science objectives, instrument, algorithm, and validation plans. |
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