Remote laser fluorescence method for oil leak detection at an excitation wavelength of 266 nm

Abstract

Subject of study. The possibility of implementing a remote laser fluorescence method to detect oil leaks on the Earth’s surface at a fluorescence excitation wavelength of 266 nm was analyzed and substantiated. Method. Laser-induced fluorescence spectra of clean oil, oil spilled on different types of soil at different time intervals after leakage, and natural and anthropogenic terrain elements were investigated. The experimental setup for remote measurements of laser-induced fluorescence spectra of oil pollution on the Earth’s surface using a laser source with a wavelength of 266 nm, pulse energy of 0.3 mJ, and a single spectral channel of a detector with a central wavelength of 510 nm and a bandwidth of 84 nm is described. The detection possibility of oil pollution against a background of natural vegetation (shrubs and grass) and soil without oil pollution were investigated remotely at a distance of 75 m using emission with a fluorescence excitation wavelength of 266 nm. Main results. Laser-induced fluorescence spectra of commercial oil from the Ryazan oil refinery and oil from Almetyevsk oil field were obtained in addition to the fluorescence spectra of vegetation, soil, and asphalt. Analysis of the data in laser-induced fluorescence spectra indicates that the maximum of the oil spectra is in the range 450–550 nm. Laser-induced fluorescence from vegetation is the largest interference signal in the detection of oil leaks on the Earth’s surface. Remote detection of oil pollution against the background of vegetation and other landscape elements was experimentally demonstrated both immediately after pollution and two days later. Practical significance. The possibility of remote monitoring of oil pollution on the Earth’s surface was experimentally demonstrated at a fluorescence excitation wavelength of 266 nm at distances close to safe aircraft flying altitudes.