dc.description | The physical and optical interaction of aerosols in atmospheric processes are complex and have high temporal and
spatial variability, representing uncertainties as, for example, the aerosol particles influence on the atmosphere energetic
balance. The Duster is a LIDAR system (Light Detection and Ranging) located in Natal / RN, capable of working with four
detection channels (355 nm, 532 nm p, 532 nm s and 1064 nm). Duster sends pulses of laser light to the atmosphere and detects
the return signal that results from the interaction of light with aerosol particles in the atmosphere. The signal detected by the
system is represented by the LIDAR equation, which describes the optical properties and the system geometric parameters.
The solution for this equation is obtained by the Klett-Fernald-Sasano Inversion Method (KFS), which extracts the inverted
optical properties as backscattering (??) and extinction (??) profiles. The present work brings the result of analysis in backscatter
profiles of the LIDAR signal in channel 532 nm during the aerosol Monitoring Campaign Long-Range Transportation Over Natal
II (MOLOTOV II) that occurred from November 2017 to February 2018. We applied the Monte Carlo method for the analysis of
the error in DUSTER measurements, which employs random numbers sequences. Two days of signal measurements were
selected, to deal with four groups files, within approximately 30 min each group (frequency acquisition every 10 seconds). N
synthetic profiles, as height function, with a random number generator, were created. Algorithms were performed, which
removed the measurements clouds, the dark profiles, the background noise and generated the Range Corrected Signal (RCS).
The KFS was applied to the synthetic profiles to obtain a set of N solutions (backscatter and extinction coefficient profiles).
The results show that the N optical property profiles presented a considerable variability, characterized by their standard
deviation. This variability, calculated as the height function, is the random error estimate of the LIDAR signal associated with
the inversion procedure. The observed aerosols, according to information from the Hysplit trajectory model, were originated
from the Sahara desert. | |