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| Titel |
Biases in regional carbon budgets from covariation of surface fluxes and weather in transport model inversions |
| VerfasserIn |
I. N. Williams, W. J. Riley, M. S. Torn, S. C. Biraud, M. L. Fischer |
| 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 ; 14, no. 3 ; Nr. 14, no. 3 (2014-02-12), S.1571-1585 |
| Datensatznummer |
250118370
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| Publikation (Nr.) |
 copernicus.org/acp-14-1571-2014.pdf |
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| Zusammenfassung |
| Recent advances in atmospheric transport model inversions could significantly
reduce uncertainties in land carbon uptake through the assimilation of CO2
concentration measurements at weekly and shorter timescales. The potential
of these measurements for reducing biases in estimated land carbon sinks
depends on the strength of covariation between surface fluxes and atmospheric
transport at these timescales and how well transport models represent this
covariation. Daily to seasonal covariation of surface fluxes and atmospheric
transport was estimated in observations at the US Southern Great Plains
Atmospheric Radiation Measurement Climate Research Facility, and compared to
an atmospheric transport model inversion (CarbonTracker). Covariation of
transport and surface fluxes was stronger in CarbonTracker than in
observations on synoptic (daily to weekly) timescales, with a wet year
(2007) having significant covariation compared to a dry year (2006).
Differences between observed and CarbonTracker synoptic covariation resulted
in a 0.3 ppm CO2 enhancement in boundary layer concentrations during the
growing season, and a corresponding enhancement in carbon uptake by 13% of
the seasonal cycle amplitude in 2007, as estimated by an offline simplified
transport model. This synoptic rectification of surface flux variability was
of similar magnitude to the interannual variability in carbon sinks alone,
and indicates that interannual variability in the inversions can be affected
by biases in simulated synoptic rectifier effects. The most significant
covariation of surface fluxes and transport had periodicities of 10 days and
greater, suggesting that surface flux inversions would benefit from improved
simulations of the effects of soil moisture on boundary layer heights and
surface CO2 fluxes. Soil moisture remote sensing could be used along with
CO2 concentration measurements to further constrain atmospheric transport
model inversions. |
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