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Titel |
Airborne lidar reflectance measurements at 1.57 μm in support of the A-SCOPE mission for atmospheric CO2 |
VerfasserIn |
A. Amediek, A. Fix, G. Ehret, J. Caron, Y. Durand |
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 ; 2, no. 2 ; Nr. 2, no. 2 (2009-11-26), S.755-772 |
Datensatznummer |
250000581
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Publikation (Nr.) |
copernicus.org/amt-2-755-2009.pdf |
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Zusammenfassung |
The characteristics of the lidar reflectance of the Earth's surface is an
important issue for the IPDA lidar technique (integrated path differential
absorption lidar) which is the proposed method for the spaceborne measurement
of atmospheric carbon dioxide within the framework of ESA's A-SCOPE project.
Both, the absolute reflectance of the ground and its variations have an
impact on the measurement sensitivity. The first aspect influences the
instrument's signal to noise ratio, the second one can lead to retrieval
errors, if the ground reflectance changes are strong on small scales. The
investigation of the latter is the main purpose of this study. Airborne
measurements of the lidar ground reflectance at 1.57 μm wavelength were
performed in Central and Western Europe, including many typical land surface
coverages as well as the open sea. The analyses of the data show, that the
lidar ground reflectance is highly variable on a wide range of spatial
scales. However, by means of the assumption of laser footprints in the order
of several tens of meters, as planned for spaceborne systems, and by means of
an averaging of the data it was shown, that this specific retrieval error is
well below 1 ppm (CO2 column mixing ratio), and so compatible with the
sensitivity requirements of spaceborne CO2 measurements. Several
approaches for upscaling the data in terms of the consideration of larger
laser footprints, compared to the one used here, are shown and discussed.
Furthermore, the collected data are compared to MODIS ground reflectance
data. |
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