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Titel |
The impact of the microphysical properties of aerosol on the atmospheric correction of hyperspectral data in coastal waters |
VerfasserIn |
C. Bassani, C. Manzo, F. Braga, M. Bresciani, C. Giardino, L. Alberotanza |
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 ; 8, no. 3 ; Nr. 8, no. 3 (2015-03-27), S.1593-1604 |
Datensatznummer |
250116234
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Publikation (Nr.) |
copernicus.org/amt-8-1593-2015.pdf |
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Zusammenfassung |
Hyperspectral imaging provides quantitative remote sensing of ocean colour by
the high spectral resolution of the water features. The
HICO™ (Hyperspectral Imager for the Coastal
Ocean) is suitable for coastal studies and monitoring. The accurate retrieval
of hyperspectral water-leaving reflectance from
HICO™ data is still a challenge. The aim of
this work is to retrieve the water-leaving reflectance from
HICO™ data with a physically based algorithm,
using the local microphysical properties of the aerosol in order to overcome
the limitations of the standard aerosol types commonly used in atmospheric
correction processing. The water-leaving reflectance was obtained using the
HICO@CRI (HICO ATmospherically Corrected Reflectance Imagery) atmospheric
correction algorithm by adapting the vector version of the Second Simulation
of a Satellite Signal in the Solar Spectrum (6SV) radiative transfer code.
The HICO@CRI algorithm was applied on to six HICO™ images acquired in the northern
Mediterranean basin, using the microphysical properties measured by the
Acqua Alta Oceanographic Tower (AAOT) AERONET site. The HICO@CRI results
obtained with AERONET products were validated with in situ measurements
showing an accuracy expressed by r2 = 0.98. Additional runs of HICO@CRI on
the six images were performed using maritime, continental and urban standard
aerosol types to perform the accuracy assessment when standard aerosol types
implemented in 6SV are used. The results highlight that the microphysical
properties of the aerosol improve the accuracy of the atmospheric correction
compared to standard aerosol types. The normalized root mean square (NRMSE)
and the similar spectral value (SSV) of the water-leaving reflectance show
reduced accuracy in atmospheric correction results when there is an increase
in aerosol loading. This is mainly when the standard aerosol type used is
characterized with different optical properties compared to the local
aerosol. The results suggest that if a water quality analysis is needed the
microphysical properties of the aerosol need to be taken into consideration
in the atmospheric correction of hyperspectral data over coastal
environments, because aerosols influence the accuracy of the retrieved
water-leaving reflectance. |
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