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| Titel |
Comparison of improved Aura Tropospheric Emission Spectrometer CO2 with HIPPO and SGP aircraft profile measurements |
| VerfasserIn |
S. S. Kulawik, J. R. Worden, S. C. Wofsy, S. C. Biraud, R. Nassar, D. B. A. Jones, E. T. Olsen, R. Jiménez, S. Park, G. W. Santoni, B. C. Daube, J. V. Pittman, B. B. Stephens, E. A. Kort, G. B. Osterman, TES team |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 6 ; Nr. 13, no. 6 (2013-03-18), S.3205-3225 |
| Datensatznummer |
250018528
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| Publikation (Nr.) |
 copernicus.org/acp-13-3205-2013.pdf |
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| Zusammenfassung |
| Thermal infrared radiances from the Tropospheric Emission Spectrometer (TES)
between 10 and 15 μm contain significant carbon dioxide (CO2)
information, however the CO2 signal must be separated from radiative
interference from temperature, surface and cloud parameters, water, and other
trace gases. Validation requires data sources spanning the range of TES
CO2 sensitivity, which is approximately 2.5 to 12 km with peak
sensitivity at about 5 km and the range of TES observations in latitude (40° S
to 40° N) and time (2005–2011). We therefore characterize Tropospheric
Emission Spectrometer (TES) CO2 version 5 biases and errors through
comparisons to ocean and land-based aircraft profiles and to the
CarbonTracker assimilation system. We compare to ocean profiles from the
first three Hiaper Pole-to-Pole Observations (HIPPO) campaigns between
40° S and 40° N with measurements between the surface and
14 km and find that TES CO2 estimates capture the seasonal and
latitudinal gradients observed by HIPPO CO2 measurements. Actual errors
range from 0.8–1.8 ppm, depending on the campaign and pressure level, and
are approximately 1.6–2 times larger than the predicted errors. The bias of
TES versus HIPPO is within 1 ppm for all pressures and datasets; however,
several of the sub-tropical TES CO2 estimates are lower than expected
based on the calculated errors. Comparisons to land aircraft profiles from
the United States Southern Great Plains (SGP) Atmospheric Radiation
Measurement (ARM) between 2005 and 2011 measured from the surface to 5 km to
TES CO2 show good agreement with an overall bias of −0.3 ppm to
0.1 ppm and standard deviations of 0.8 to 1.0 ppm at different pressure
levels. Extending the SGP aircraft profiles above 5 km using AIRS or
CONTRAIL measurements improves comparisons with TES. Comparisons to
CarbonTracker (version CT2011) show a persistent spatially dependent bias
pattern and comparisons to SGP show a time-dependent bias of
−0.2 ppm yr−1. We also find that the predicted sensitivity of the TES
CO2 estimates is too high, which results from using a multi-step
retrieval for CO2 and temperature. We find that the averaging kernel in
the TES product corrected by a pressure-dependent factor accurately reflects
the sensitivity of the TES CO2 product. |
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