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| Titel |
Estimation of a "radiatively correct" black carbon specific absorption during the Mexico City Metropolitan Area (MCMA) 2003 field campaign |
| VerfasserIn |
J. C. Barnard, E. I. Kassianov, T. P. Ackerman, K. Johnson, B. Zuberi, L. T. Molina, M. J. Molina |
| 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 ; 7, no. 6 ; Nr. 7, no. 6 (2007-03-27), S.1645-1655 |
| Datensatznummer |
250004835
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| Publikation (Nr.) |
 copernicus.org/acp-7-1645-2007.pdf |
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| Zusammenfassung |
| During the Mexico City Metropolitan Area (MCMA) field campaign of 2003,
measurements of the shortwave radiation field allowed the inference of the
black carbon (BC) specific absorption, αλ, defined as the
monochromatic absorption cross section per unit mass (with units of
m2/g). The averaged values of αλ derived from the method
here are either 8.9 m2/g or 8.2 m2/g at 500 nm, depending upon the
physical and optical parameters assumed for BC. These results are reasonably
consistent with those of Schuster et al. (2005), 9.5 m2/g, and
Baumgartner et al. (2002), 7.0 m2/g, both measured at 550 nm. The
αλ values reported in this paper should only be considered
effective, "radiatively correct" values because when used in radiative
transfer calculations the calculated irradiances match the measured
irradiances at 500 nm. The specific absorption so defined can assume a wide
range of values, depending upon: (1) the assumptions made prior to the
retrieval (e.g., shell/core aerosol configuration), and (2) values chosen
for BC density and refractive index. The range of possible values is large,
corresponding to a "worst case" uncertainty of about ±70%,
assuming that all errors are additive and of the same sign so that no error
cancellation occurs. |
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