Metrological assessment of LIDAR signals in water

Over the years many private companies and governmental institutions have adopted environmental monitoring as an effective practice to minimize harmful impacts on the environment. Remote monitoring is unquestionably a versatile alternative for detecting possible leaking of noxious substances before they become apparent. LIDAR provides a reliable technique for measurements of pigments in seawater. An investigation was carried out to: (i) assess different procedures to improve the signal-to-noise relationship; (ii) preserve the integrity of the wavelength bandwidth of the fluorescence spectrum; (iii) verify the repeatability of wavelength measurements associated with local maximum of the Raman scattering curve of seawater and chlorophyll-a. Two approaches were adopted to calibrate the equipment: in the laboratory, by evaluating fluorescence signal fluctuations of the Raman scattering in seawater for different equipment parameters and on-site, by measuring relative concentrations of chlorophyll-a in seawater for different schemes. An experimental arrangement was eventually set up as calibration standard.