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Titel |
Retrieval of aerosol parameters from the oxygen A band in the presence of chlorophyll fluorescence |
VerfasserIn |
A. F. J. Sanders, J. F. Haan |
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 ; 6, no. 10 ; Nr. 6, no. 10 (2013-10-18), S.2725-2740 |
Datensatznummer |
250085086
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Publikation (Nr.) |
copernicus.org/amt-6-2725-2013.pdf |
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Zusammenfassung |
We have investigated the precision of retrieved aerosol parameters for a generic
aerosol retrieval algorithm over vegetated land using the O2 A band.
Chlorophyll fluorescence is taken into account in the forward model.
Fluorescence emissions are modeled as isotropic contributions to the
upwelling radiance field at the surface and they are retrieved along with
aerosol parameters. Precision is calculated by propagating measurement
errors and a priori errors, including model parameter errors, using the
forward model's derivatives. Measurement errors consist of noise and
calibration errors. The model parameter errors considered are related to the
single scattering albedo, surface pressure and temperature profile. We
assume that measurement noise is dominated by shot noise; thus, results
apply to grating spectrometers in particular. We describe precision for various atmospheric states,
observation geometries and spectral resolutions of the instrument in a number of retrieval
simulations. These
precision levels can be compared with user requirements. A comparison of
precision estimates with the literature and an analysis of the dependence on
the a priori error in the fluorescence emission indicate that aerosol
parameters can be retrieved in the presence of chlorophyll fluorescence: if
fluorescence is present, fluorescence emissions should be included in the
state vector to avoid biases in retrieved aerosol parameters. |
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