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| Titel |
Carbon-13 isotope composition of the mean CO2 source in the urban atmosphere of Krakow, southern Poland |
| VerfasserIn |
Miroslaw Zimnoch, Alina Jasek, Kazimierz Różański |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250094143
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| Publikation (Nr.) |
 EGU/EGU2014-9537.pdf |
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| Zusammenfassung |
| Quantification of carbon emissions in urbanized areas constitutes an important part of the
current research on the global carbon cycle. As the carbon isotopic composition
of atmospheric carbon dioxide can serve as a fingerprint of its origin, systematic
observations of δ13CO2 and/or Δ14CO2, combined with atmospheric CO2mixing
ratio measurements can be used to better constrain the urban sources of this gas.
Nowadays, high precision optical analysers based on absorption of laser radiation in
the cavity allow a real-time monitoring of atmospheric CO2 concentration and
its 13CO2/12CO2 ratio, thus enabling better quantification of the contribution of
different anthropogenic and natural sources of this gas to the local atmospheric
CO2load.
Here we present results of a 2-year study aimed at quantifying carbon isotopic signature
of the mean CO2 source and its seasonal variability in the urban atmosphere of Krakow,
southern Poland. The Picarro G2101-i CRDS isotopic analyser system for CO2and
13CO2/12CO2 mixing ratio measurements has been installed at the AGH University of
Science and Technology campus in July 2011. Air inlet was located at the top of a 20m tower
mounted on the roof of the faculty building (ca. 42m a.g.l.), close to the city centre. While
temporal resolution of the analyser is equal 1s, a 2-minute moving average was used for
calculations of δ13CO2 and CO2 mixing ratio to reduce measurement uncertainty. The
measurements were calibrated against 2 NOAA (National Oceanic and Atmospheric
Administration) primary standard tanks for CO2 mixing ratio and 1 JRAC (Jena Reference
Air Cylinder) isotope primary standard for δ13C. A Keeling approach based on
two-component mass and isotope balance was used to derive daily mean isotopic signatures
of local CO2 from individual measurements of δ13CO2 and CO2 mixing ratios.
The record covers a 2-year period, from July 2011 to July 2013. It shows a clear
seasonal pattern, with less negative and less variable δ13CO2 values during the
late spring, summer and early autumn, and more negative and more noisy δ13CO2
values during the rest of the year. The mean δ13CO2 value for summer months
(May-September) is equal –29.44±0.12o while during winter it drops to –33.29±0.28oṪhe
isotopic signature of mean summer CO2 source represents strong biogenic CO2
emissions (δ13CO2 ~= –28) mixed with isotopically similar CO2 emitted by car traffic
in the city (δ13CO2 ~= –30). During the cold period, biogenic source becomes
negligible, while anthropogenic CO2 emissions are enhanced by heating of the
households. The CO2 sources associated with heating represent a much wider range of
isotope composition (from –24ofor coal burning, –28 ofor burning of wood in
fireplaces, down to –54 ofor heating systems supplied with natural gas of Siberian
origin).
Acknowledgement: This work is supported by the Ministry of Science and Higher
Education (project No. 817.N-COST/2010/0 and the statutory funds of the AGH University
of Science and Technology, project no. 11.11.220.01). |
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