Determination of aquatic parameters by a time-resolved laser fluorosensor operating from a helicopter

A time resolved lidar fluorosensor operated from a helicopter is described. This sensor is particularly suitable for oil identification in a slick on the sea surface and to perform accurate measurements on the water beam attenuation coefficient in addition to the evaluation of the dissolved organic matter (DOM) content in the water column. The procedure to evaluate these parameters is presented and discussed. Two validation campaigns were performed over the Ligurian Sea in July and over the Adriatic Sea in December 1991. The results conformed to what was expected from the simulation experiments. In particular, the possibility of measuring the water beam extinction coefficient at the excitation wavelength (355 nm) and at the water Raman wavelength (404 nm) from the time dependence of the backscattering and Raman signals of a single shot was demonstrated. It was therefore possible to draw profiles of the water transparency and of the DOM fluorescence intensity along the flight line.