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A sensitivity study of the LIdar-Radiometer Inversion Code (LIRIC) using selected cases from Thessaloniki, Greece database

A sensitivity study of the LIdar-Radiometer Inversion Code (LIRIC) using selected cases from Thessaloniki, Greece database

The LIdar-Radiometer Inversion Code (LIRIC) provides vertical aerosol concentration profiles by combining measurements carried out with a multi-wavelength lidar and a sun photometer.

The methodology requires pre-defining a set of input parameters. In this study we investigate the effect of those user-defined input parameters to the output optical profiles and microphysical properties using a Raman lidar and a Cimel sunphotometer located at Thessaloniki, Greece.

The sensitivity study involves three tests. We first evaluate the selection of the regularization parameters needed for the algorithm to initialize the iteration process. The latter two tests consider the impact of the boundary limits at the top/bottom (upper/lower limit) of the signal to the derived concentration profiles. The aforementioned tests were applied to two different aerosol scenarios, a Saharan dust event and a continental pollution case.

We concluded that the largest uncertainties are introduced when varying the lower limit (more than 35 %) regardless of the aerosol type or mode (fine/coarse). Varying the regularization parameters resulted in an uncertainty of 20 %, and the selection of upper limit led to discrepancies of less than 3 %. In conclusion, this sensitivity study indicates that future LIRIC users should apply an overlap function to the lidar signals before applying the methodology for minimizing the uncertainties in the near range.

More information:

Maria Filioglou, tel. +358 50 463 9930, maria.filioglou@fmi.fi

M. Filioglou, N. Siomos, A. Poupkou, S. Dimopoulos, A. Chaikovsky & D. Balis. (2017). A sensitivity study of the LIdar-Radiometer Inversion Code (LIRIC) using selected cases from Thessaloniki, Greece database. International Journal of Remote Sensing. 39(2), p.:315-333. doi: http://dx.doi.org/10.1080/01431161.2017.1384589.

 

 

 


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