Remote Detection of Oil Pollution
Development of Laser Methods for Remote Detection of Oil Pollutions on Disturbed Sea Surface and Measurement of Petrochemical Product Film Thickness
Tech Area / Field
- ENV-MIN/Monitoring and Instrumentation/Environment
- ENV-WPC/Water Pollution and Control/Environment
8 Project completed
Senior Project Manager
Ryzhova T B
MGTU (Moscow State Technical University), Russia, Moscow
- University of Illinois At Urbana-Champaign, USA, IL, Urbana
Project summaryProposed Project is aimed at development of laser methods of remote detection of oil pollutions on disturbed sea surface, and methods to measure the oil-product film thickness from aircrafts.
Laser methods of remote sounding are the most promising ones to monitor water areas in order to detect oil pollutions on the water surface and to measure petrochemical product film thicknesses.
Remote indication of pollutions by laser method is based on the difference in reflecting, scattering or fluorescent properties of pure water and that covered by oil film.
The method based on active laser detection of the water surface and registration of laser radiation reflected by oil films, is most challenging laser method for remote detecting oil pollutions on the water surface and measuring their film thickness. It allows to perform the detection from aircraft at any altitude.
Oil film detection by active laser location is usually realized within the near (1.06 m) or medium (10.06 m) spectrum range of infra-red radiation; intensity of the radiation reflected from water surface is measured, the contrast between registered intensities of radiation reflected from pure water surface and that covered by oil film, is thus determined. There is an opportunity not to make absolute measurements by lidar (laser radar) at detecting oil films. At the flight beginning (when lidar is mounted on board of flying vehicle), lidar registers a signal reflected from pure water. Signal registered by lidar increases sharply when the laser illumination spot falls on the oil slick (spreads of oil or petroleum products), and the contrast arises between the area under investigation and pure water surface.
The method described gives reliable spotting of oil contaminations of sea surface, however, it has a shortage, namely, sea areas without oil films can be identified as “oil pollutions”. The fact is that the area with high intensity of reflected radiation can be:
– water area with smoothened waves caused by wind (for example, due to wind “shadow” behind the island or high coast);
– area with high reflectivity (sea surface reflectivity can vary not only because of the oil contamination but also while presence foam, films of biological nature, algae, etc).
It is proposed to develop a new measurement method and algorithm of the measurement result processing that would allow to distinguish oil-polluted zones from the sea surface areas with smoothed waves (for example, windless regions behind high coasts or islands), and from high-reflectivity areas (for example, due to foam presence on the water surface). Therefore, presence of oil slicks on the sea surface will be decided with high adequacy.
Underlying physics for remote measurement of the oil film thickness on sea surface by the active laser location method consists in presence of a dependence of the “air – oil film – water”- system reflectivity on the radiation wavelength and oil film thickness.
It is proposed to develop a new method to measure oil-film thickness on water surface that is based on using the laser radiation source retuned on the length of its generated wave.
The Project authors being specialists in the field of laser detection of the atmosphere and sea surface have certain scientific experience answering the purpose to realize the Project; the theoretical grounds of pulse laser detection of the waved sea surface are elaborated by them.