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| Titel |
Aerosol type Identification over the Arabian Sea in the pre-monsoon season during the ICARB campaign |
| VerfasserIn |
M. C. R. Kalapureddy, D. G. Kaskaoutis, P. Ernest Raj, P. C. S. Devara, H. D. Kambezidis, P. G. Kosmopoulos, P. T. Nastos |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250023707
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| Zusammenfassung |
| A discrimination method of the different aerosol types over Arabian Sea (AS) during the
ICARB-06 campaign is achieved using values of AOD at 500 nm (AOD500) and Ångström
exponent (α) in the spectral band 340-1020 nm (α340-1020). Spectral AOD and Ångström
exponent data were analyzed to obtain information about the adequacy of the simple
use of the Ångström exponent for characterizing the aerosols, and for exploring
possibilities for a more efficient characterization of the aerosols. For this purpose,
appropriate thresholds for AOD500 and α340-1020 are applied. It is shown that a single
aerosol type in a given location over AS can exist only under specific conditions (e.g.
anthropogenic emissions or dust outbreaks), while the presence of well-mixed aerosols is
the usual situation. Our analysis indicates that the dominant aerosol types change
significantly in the different regions of AS (coastal AS, middle AS and far AS). Thus, the
urban/industrial aerosols are mainly observed in coastal AS, the desert-dust particles in
middle and northern AS, while clear maritime conditions mainly occur in far AS.
This is achieved by taking advantage of the spectral variation of α, the so-called
curvature. The results show that the spectral curvature can provide important additional
information about the different aerosol types, and can effectively be used as a tool
for their discrimination, since the fine-mode aerosols exhibit negative curvature,
while the coarse-mode particles positive. The correlation between the coefficients a1
and a2 with the Ångström exponent α, and the atmospheric turbidity, is further
investigated.
Keywords: Aerosol optical properties; Aerosol type; cruise measurements; Arabian Sea;
pre-monsoon ICARB. |
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