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| Titel |
Direct radiative effect by brown carbon over the Indo-Gangetic Plain |
| VerfasserIn |
A. Arola, G. L. Schuster, M. R. A. Pitkänen, O. Dubovik, H. Kokkola, A. V. Lindfors, T. Mielonen, T. Raatikainen, S. Romakkaniemi, S. N. Tripathi, H. Lihavainen |
| 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 ; 15, no. 22 ; Nr. 15, no. 22 (2015-11-17), S.12731-12740 |
| Datensatznummer |
250120165
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| Publikation (Nr.) |
 copernicus.org/acp-15-12731-2015.pdf |
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| Zusammenfassung |
| The importance of light-absorbing organic aerosols, often called brown carbon
(BrC), has become evident in recent years. However, there have been
relatively few measurement-based estimates for the direct radiative effect of
BrC so far. In earlier studies, the AErosol RObotic NETwork
(AERONET)-measured aerosol absorption optical depth (AAOD) and absorption
Angstrom exponent (AAE) were exploited. However, these two pieces of
information are clearly not sufficient to separate properly carbonaceous
aerosols from dust, while imaginary indices of refraction would contain more
and better justified information for this purpose. This is first time that
the direct radiative effect (DRE) of BrC is estimated by exploiting the
AERONET-retrieved imaginary indices. We estimated it for four sites in the
Indo-Gangetic Plain (IGP), Karachi, Lahore, Kanpur and Gandhi College. We
found a distinct seasonality, which was generally similar among all the
sites, but with slightly different strengths. The monthly warming effect up
to 0.5 W m−2 takes place during the spring season. On the other hand,
BrC results in an overall cooling effect in the winter season, which can
reach levels close to −1 W m−2. We then estimated similarly also the
DRE of black carbon and total aerosol, in order to assess the relative
significance of the BrC radiative effect in the radiative effects of other
components. Even though BrC impact seems minor in this context, we
demonstrated that it is not insignificant. Moreover, we demonstrated that it is
crucial to perform spectrally resolved radiative transfer calculations to obtain
good estimates for the DRE of BrC. |
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