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| Titel |
Influence of aerosol and surface reflectance variability on hyperspectral observed radiance |
| VerfasserIn |
C. Bassani, R. M. Cavalli, P. Antonelli |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 5, no. 6 ; Nr. 5, no. 6 (2012-06-01), S.1193-1203 |
| Datensatznummer |
250002960
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| Publikation (Nr.) |
 copernicus.org/amt-5-1193-2012.pdf |
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| Zusammenfassung |
| Current aerosol retrievals based on visible and near infrared remote-sensing,
are prone to loss of accuracy, where the assumptions of the applied algorithm
are violated. This happens mostly over land and it is related to
misrepresentation of specific aerosol conditions or surface properties. New
satellite missions, based on high spectral resolution instruments, such as
PRISMA (Hyperspectral Precursor of the Application Mission), represent a
valuable opportunity to improve the accuracy of τa550 retrievable
from a remote-sensing system developing new atmospheric measurement
techniques. This paper aims to address the potential of these new observing
systems in more accurate retrieving τa550, specifically over land in
heterogeneous and/or homogeneous areas composed by dark and bright targets.
The study shows how the variation of the hyperspectral observed radiance can
be addressed to recognise a variation of Δτa550 = 0.02. The goal
has been achieved by using simulated radiances by combining two aerosol
models (urban and continental) and two reflecting surfaces: dark
(represented by water) and bright (represented by sand) for the PRISMA
instrument, considering the environmental contribution of the observed
radiance, i.e., the adjacency effect. Results showed that, in the continental
regime, the expected instrument sensitivity would allow for retrieval
accuracy of the aerosol optical thickness at 550 nm of 0.02 or better,
with a dark surface surrounded by dark areas. The study also showed that for
the urban regime, the surface plays a more significant role, with a bright
surface surrounded by dark areas providing favourable conditions for the
aerosol load retrievals, and dark surfaces representing less suitable
situations for inversion independently of the surroundings. However, over
all, the results obtained provide evidence that high resolution observations
of Earth spectrum between 400 and 1000 nm would allow for a significant
improvement of the accuracy of the τa550 for
anthropogenic/natural
aerosols over land. |
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