A SHORE-BASED LIDAR FOR COASTAL SEAWATER MONITORING

Abstract

The paper presents a description of a shore based lidar which can play a key role in developing a system for continuous express monitoring of coastal seawater areas. Results of field tests in the region of the Blue Bay (Black Sea, near Gelendzhik) are reported. Echo-signals are obtained with excitation wavelengths of 532, 355 and 266 nm (2 nd , 3 rd and 4 th harmonics of a YAG:Nd laser). The dependencies of an echo-signal (in this case water Raman scattering) on the sensing distance of the laser beam are investigated. The results obtained appear to correlate well with the theory of laser remote sensing under large incidence angles, in which wind waves are taken into account. In the experiments, laser radiation with 532 nm wavelength at 10 Hz repetition rate, with 10 ns pulse duration and 10 mJ pulse energy was used. The sensing distance was up to 100 m at a sensing angle of approx. 80°. The possibility of increasing the sensing distance up to 0.5-1 km is shown. Therefore, this device can be used for monitoring of bays similar to the Blue Bay or other vitally important areas.