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Titel |
Top-down estimation of carbon monoxide emissions from the Mexico Megacity based on FTIR measurements from ground and space |
VerfasserIn |
W. Stremme, M. Grutter, C. Rivera, A. Bezanilla, A. R. Garcia, I. Ortega, M. George, C. Clerbaux, P.-F. Coheur, D. Hurtmans, J. W. Hannigan, M. T. Coffey |
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. 3 ; Nr. 13, no. 3 (2013-02-01), S.1357-1376 |
Datensatznummer |
250017634
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Publikation (Nr.) |
copernicus.org/acp-13-1357-2013.pdf |
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Zusammenfassung |
Continuous carbon monoxide (CO) total column densities above the Universidad
Nacional Autónoma de México (UNAM) campus in Mexico City have been
derived from solar absorption infrared spectroscopic measurements since
October 2007. Its diurnal evolution is used in the present study in
conjunction with other ground-based and satellite data to develop a top-down
emission estimate of the annual CO emission of the Mexico City Metropolitan
Area (MCMA). The growth-rate of the total column around noon under low
ventilation conditions is calculated and allows us to derive the average
surface emission-flux at UNAM, while similar measurements taken at the edge
of the MCMA in Tecámac provide information on background CO levels in the
Mexico basin. Based on 3 yr of measurements, CO column measurements from the
Infrared Atmospheric Sounding Interferometer (IASI) satellite instrument are
used to reconstruct the spatial distribution of this anthropogenic pollutant
over the MCMA. The agreement between the measured columns of the satellite
and ground-based measurements is excellent, particularly when a comparison
strategy based on time-displaced air masses is used. The annual emission of
the Mexico Megacity is estimated to be (2.15 ± 0.5) Tg yr−1 for
the year 2008, while the official inventory for that year reported
1.6 Tg yr−1. The difference is slightly higher than the conservative
uncertainty estimated in this work suggesting that the emission might be
underestimated by the conventional bottom-up method. A larger discrepancy is
found in the spatial distribution of the emissions, when comparing the
emission flux over UNAM (derived from the ground-based measurement) with that
of the inventory integrated over a representative area. The methodology
presented here represents a new and useful strategy to evaluate the
contribution of megacities to the global anthropogenic gas emissions.
Additionally, three different strategies to compare ground and space-based
measurements above an inhomogeneous and strongly contaminated area like
Mexico City are presented and discussed. |
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