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| Titel |
CO2 and its correlation with CO at a rural site near Beijing: implications for combustion efficiency in China |
| VerfasserIn |
Y. Wang, J. W. Munger, S. Xu, M. B. McElroy, J. Hao, C. P. Nielsen, H. Ma |
| 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 ; 10, no. 18 ; Nr. 10, no. 18 (2010-09-21), S.8881-8897 |
| Datensatznummer |
250008785
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| Publikation (Nr.) |
 copernicus.org/acp-10-8881-2010.pdf |
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| Zusammenfassung |
| Although China has surpassed the United States as the world's largest carbon
dioxide emitter, in situ measurements of atmospheric CO2 have been
sparse in China. This paper analyzes hourly CO2 and its correlation
with CO at Miyun, a rural site near Beijing, over a period of 51 months (Dec
2004 through Feb 2009). The CO2-CO correlation analysis evaluated
separately for each hour of the day provides useful information with
statistical significance even in the growing season. We found that the
intercept, representing the initial condition imposed by global distribution of
CO2 with influence of photosynthesis and respiration, exhibits diurnal
cycles differing by season. The background CO2 (CO2,b) derived
from Miyun observations is comparable to CO2 observed at a Mongolian
background station to the northwest. Annual growth of overall mean CO2
at Miyun is estimated at 2.7 ppm yr−1 while that of CO2,b is
only 1.7 ppm yr−1 similar to the mean growth rate at northern
mid-latitude background stations. This suggests a relatively faster increase
in the regional CO2 sources in China than the global average,
consistent with bottom-up studies of CO2 emissions. For air masses with
trajectories through the northern China boundary layer, mean winter
CO2/CO correlation slopes (dCO2/dCO) increased by 2.8 ± 0.9 ppmv/ppmv or 11% from 2005–2006 to
2007–2008, with CO2 increasing by
1.8 ppmv. The increase in dCO2/dCO indicates improvement in overall
combustion efficiency over northern China after winter 2007, attributed to
pollution reduction measures associated with the 2008 Beijing Olympics.
The observed CO2/CO ratio at Miyun is 25% higher than the bottom-up
CO2/CO emission ratio, suggesting a contribution of respired CO2
from urban residents as well as agricultural soils and livestock in the
observations and uncertainty in the emission estimates. |
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