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| Titel |
Linear estimation of particle bulk parameters from multi-wavelength lidar measurements |
| VerfasserIn |
I. Veselovskii, O. Dubovik, A. Kolgotin, M. Korenskiy, D. N. Whiteman, K. Allakhverdiev, F. Huseyinoglu |
| 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. 5 ; Nr. 5, no. 5 (2012-05-21), S.1135-1145 |
| Datensatznummer |
250002869
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| Publikation (Nr.) |
 copernicus.org/amt-5-1135-2012.pdf |
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| Zusammenfassung |
An algorithm for linear estimation of aerosol bulk properties such as
particle volume, effective radius and complex refractive index from
multiwavelength lidar measurements is presented. The approach uses the fact
that the total aerosol concentration can well be approximated as a linear
combination of aerosol characteristics measured by multi-wavelength lidar.
Therefore, the aerosol concentration can be estimated from lidar
measurements without the need to derive the size distribution, which entails
more sophisticated procedures. The definition of the coefficients required
for the linear estimates is based on an expansion of the particle size
distribution in terms of the measurement kernels. Once the coefficients are
established, the approach permits fast retrieval of aerosol bulk properties
when compared with the full regularization technique. In addition, the
straightforward estimation of bulk properties stabilizes the inversion
making it more resistant to noise in the optical data.
Numerical tests demonstrate that for data sets containing three aerosol
backscattering and two extinction coefficients (so called 3β + 2α) the uncertainties in the retrieval of particle volume and surface area
are below 45% when input data random uncertainties are below 20%.
Moreover, using linear estimates allows reliable retrievals even when the
number of input data is reduced. To evaluate the approach, the results
obtained using this technique are compared with those based on the
previously developed full inversion scheme that relies on the regularization
procedure. Both techniques were applied to the data measured by
multiwavelength lidar at NASA/GSFC. The results obtained with both methods
using the same observations are in good agreement. At the same time, the
high speed of the retrieval using linear estimates makes the method
preferable for generating aerosol information from extended lidar
observations. To demonstrate the efficiency of the method, an extended time
series of observations acquired in Turkey in May 2010 was processed using
the linear estimates technique permitting, for what we believe to be the
first time, temporal-height distributions of
particle parameters. |
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