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| Titel |
Sensitivity of simulated CO2 concentration to regridding of global fossil fuel CO2 emissions |
| VerfasserIn |
X. Zhang, K. R. Gurney, P. Rayner, Y. Liu, S. Asefi-Najafabady |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1991-959X
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Model Development ; 7, no. 6 ; Nr. 7, no. 6 (2014-12-04), S.2867-2874 |
| Datensatznummer |
250115789
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| Publikation (Nr.) |
 copernicus.org/gmd-7-2867-2014.pdf |
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| Zusammenfassung |
| Errors in the specification or utilization of fossil fuel CO2 emissions
within carbon budget or atmospheric CO2 inverse studies can alias the
estimation of biospheric and oceanic carbon exchange. A key component in the
simulation of CO2 concentrations arising from fossil fuel emissions is
the spatial distribution of the emission near coastlines. Regridding of
fossil fuel CO2 emissions (FFCO2) from fine to coarse grids to
enable atmospheric transport simulations can give rise to mismatches between
the emissions and simulated atmospheric dynamics which differ over land or
water. For example, emissions originally emanating from the land are emitted
from a grid cell for which the vertical mixing reflects the roughness and/or
surface energy exchange of an ocean surface. We test this potential
"dynamical inconsistency" by examining simulated global atmospheric
CO2 concentration driven by two different approaches to regridding
fossil fuel CO2 emissions. The two approaches are as follows: (1) a commonly used
method that allocates emissions to grid cells with no attempt to ensure
dynamical consistency with atmospheric transport and (2) an improved method
that reallocates emissions to grid cells to ensure dynamically consistent
results. Results show large spatial and temporal differences in the
simulated CO2 concentration when comparing these two approaches. The
emissions difference ranges from −30.3 TgC grid cell−1 yr−1 (−3.39 kgC m−2 yr−1)
to +30.0 TgC grid cell−1 yr−1 (+2.6 kgC m−2 yr−1) along
coastal margins. Maximum simulated annual mean CO2 concentration
differences at the surface exceed ±6 ppm at various locations and
times. Examination of the current CO2 monitoring locations during the
local afternoon, consistent with inversion modeling system sampling and
measurement protocols, finds maximum hourly differences at 38 stations
exceed ±0.10 ppm with individual station differences exceeding −32 ppm.
The differences implied by not accounting for this dynamical
consistency problem are largest at monitoring sites proximal to large
coastal urban areas and point sources. These results suggest that studies
comparing simulated to observed atmospheric CO2 concentration, such as
atmospheric CO2 inversions, must take measures to correct for this
potential problem and ensure flux and dynamical consistency. |
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