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| Titel |
Profiling tropospheric CO2 using Aura TES and TCCON instruments |
| VerfasserIn |
L. Kuai, J. Worden, S. Kulawik, K. Bowman, M. Lee, S. C. Biraud, J. B. Abshire, S. C. Wofsy, V. Natraj, C. Frankenberg, D. Wunch, B. Connor, Charles Miller, C. Roehl, R.-L. Shia, Y. Yung |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 6, no. 1 ; Nr. 6, no. 1 (2013-01-10), S.63-79 |
| Datensatznummer |
250017371
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| Publikation (Nr.) |
 copernicus.org/amt-6-63-2013.pdf |
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| Zusammenfassung |
| Monitoring the global distribution and long-term variations of CO2
sources and sinks is required for characterizing the global carbon budget.
Total column measurements are useful for estimating regional-scale fluxes;
however, model transport remains a significant error source, particularly
for quantifying local sources and sinks. To improve the capability of
estimating regional fluxes, we estimate lower tropospheric CO2
concentrations from ground-based near-infrared (NIR) measurements with
space-based thermal infrared (TIR) measurements. The NIR measurements are
obtained from the Total Carbon Column Observing Network (TCCON) of solar
measurements, which provide an estimate of the total CO2 column amount.
Estimates of tropospheric CO2 that are co-located with TCCON are
obtained by assimilating Tropospheric Emission Spectrometer (TES) free
tropospheric CO2 estimates into the GEOS-Chem model. We find that
quantifying lower tropospheric CO2 by subtracting free tropospheric
CO2 estimates from total column estimates is a linear problem, because
the calculated random uncertainties in total column and lower tropospheric
estimates are consistent with actual uncertainties as compared to aircraft
data. For the total column estimates, the random uncertainty is about 0.55 ppm
with a bias of −5.66 ppm, consistent with previously published results.
After accounting for the total column bias, the bias in the lower
tropospheric CO2 estimates is 0.26 ppm with a precision (one standard
deviation) of 1.02 ppm. This precision is sufficient for capturing the
winter to summer variability of approximately 12 ppm in the lower
troposphere; double the variability of the total column. This work shows
that a combination of NIR and TIR measurements can profile CO2 with the
precision and accuracy needed to quantify lower tropospheric CO2
variability. |
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