Optical Methods for Water Pollution Monitoring (original) (raw)
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Evaluation of water pollution by LIF LIDAR
Within the framework of ERA-AMPERA Program (Project DEOSOM), INOV is developing a modular sensor for short and intermediate range remote oil spill detection and evaluation. The sensor is based on laser induced fluorescence light detection and ranging (LIF LIDAR), an innovative, efficient and fast water inspection method, capable of providing quantitative data for chemical pollution and biomass distribution studies over large water bodies with high spatiotemporal resolution. The sensor can be installed aboard watercraft and used for intensive surveillance of harbourages, rivers, channels, and coastal waters. The paper presents experimental evidence of the applicability of a LIF LIDAR sensor based on a solid-state Q-switched Nd:YAG laser and a CCD spectrometer for oil spill surveillance. The detection was laboratory tested with typical crude brands transported and processed in the Mediterranean region and the dynamics of oil film on the water surface investigated. Good sensitivity of the sensor in the UV range of 400-500 nm enables the LIF spectra to be calibrated using water Raman scattering peak and the LIF emission of very heavy oils and dissolved organic matter to be reliably detected. The feasibility of the method was demonstrated by successful detecting and analysing the spreading of an experimental spill of rhodamine in the Atlantic Ocean coastal waters near Vigo (Spain).
Laser Remote Sensing of Coastal and Terrestrial Pollution by FLS-Lidar
ABSTRACT The paper presents recent results of field experiments with airborne fluorescent lidar FLS-A based on excimer,laser and multichannel,detector. Helicopter installation was used to monitor water and land areas of oil transportation and storage. Techniques for real-time data acquisition and processing are described based on compiled and systematized library of LIF spectra of various underlying surfaces. The field tests have proved the ability of FLS-A lidar to distinguish the fluorescence of minor oil pollution on different spectral backgrounds usually recorded in airborne measurements. Further lidar developments are discussed. Keywords:oil pollution, lidar, laser-induced fluorescence, remote sensing methods
Laser remote sensing of coastal and terrestrial pollution by fls-lidar,” in EARSeL eProceedings
2003
The paper presents recent results of field experiments with airborne fluorescent lidar FLS-A based on excimer laser and multichannel detector. Helicopter installation was used to monitor water and land areas of oil transportation and storage. Techniques for real-time data acquisition and process-ing are described based on compiled and systematized library of LIF spectra of various underlying surfaces. The field tests have proved the ability of FLS-A lidar to distinguish the fluorescence of minor oil pollution on different spectral backgrounds usually recorded in airborne measurements. Further lidar developments are discussed.
Metrological assessment of LIDAR signals in water
Measurement, 2011
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.
Lidar application in airborne monitoring of eutrophication and chemical pollution
The work explores capabilities of the multi-wavelength laser remote sensing technique in the on-line monitoring of coastal waters. The conceptual design of the Fluorescent Lidar Spectrometer (FLS)compact, multipurpose, active remote sensor -is described. Its modular scheme allows to operate the lidar efficiently and economically onboard a small airplane or a helicopter. The presented laser sensing data on oil pollution, dissolved organic matter (DOM), phytoplankton and phytobenthos prove the approach potential for the monitoring of marine and coastal environments. Future developments are discussed.
Compact Lidar For Remote Sensing Of WaterPollution
1997
It is presented the results of oil products and dissolved organic matter water pollution detection and mapping. The simultaneous detection of laser induced fluorescence and water molecule Raman scattering signals gives the possibility of chlorophyll a concentration measurements and biological productivity evaluations. The lidar setup includes: a Nd:YAG laser, compacted and stable to vibration, with frequency doubling (second harmonic pulse energy 200 mJ, pulse duration 10 ns, repetition rate 10 Hz); a receiving - transmitting device with a mirror telescope of 15 cm diameter; a polychromator; and a recording system consisting of a gated light amplifier based on an electron-optical converter and a CCD camera. The results of laboratory and field experiments on dispersed oil products in Guanabara Bay, Rio de Janeiro, Brazil, and some other water basins will be presented. These experiment data supply the database of Brazilian monitoring program for recuperation of Guanabara Bay ecosystem.
LIDAR Measurement of the Attenuation Coefficient of Natural Waters
22nd Internation …, 2004
This paper illustrates a method for the remote measurement of the attenuation coefficient of natural water as a function of wavelength. This measurement is carried out with a fluorescence lidar system which has both spectral and temporal resolution, thus allowing the remote monitoring of volume targets, such as water column profiles. This fluorescence lidar has been designed and developed by the authors in view of an automatic operation from ship or buoy.
Locating Water Pollution and Shore Discharges in Coastal Zone and Inland Waters with FLS Lidar
2006
The paper reviews results of field studies and pilot projects with airborne Fluorescent Laser Spec- trometers (FLS-lidars) carried out in 2003-2004 in sea and lake waters as well as watersheds. Those studies were aimed at locating areas with water quality deviations from normal state due to municipal and agriculture discharges and chemical pollution. The studies were conducted in On- tario
Total luminescent spectroscopy for remote laser diagnostics of natural water conditions
Applied Optics, 1991
In undertaking the rapid diagnostics of water conditions (for organic impurities, eutrophication etc.), it is expedient to confine the effort to establishing the statistically normal state and departures from it rather than to seek the full chemical composition of the medium. What others have termed spectral signatures obtained by such methods as total luminescent spectroscopy can serve as representative indicators of both background conditions and those deviating from the normal. In this paper we show how, with the aid of laboratory catalogs of spectral signatures, it is possible to detect oil pollution at levels substantially below those of slicks (of a few microliters per liter) and to identify groups of pollutants (by remote sensing). And we describe a spectroscopic lidar vie developed for marine studies.
Lidar Remote Sensing for Industry and Environment Monitoring III, 2003
The paper overviews capabilities of a multi-wavelength laser remote sensing technique in real-time analytical monitoring of aquatic and terrestrial targets. The conceptual design of the Fluorescent Lidar Spectrometer (FLS) -a compact, multipurpose analytical lidar -is described. Its modular architecture allows efficient research and routine monitoring applications from small boats or aircraft. Depending on the application requirements, the FLS analytical performance can be optimized with features such as variable excitation wavelengths and high-speed, gated hyperspectral detection. The Spectral Fluorescent Signature (SFS) concept, which forms the background for the FLS functioning, has been successful in the detection and identification of trace organics in various environmental, industrial and other mixtures.