Laser Environmental Airborne Fluorosensor Research Articles

LASER FLUOROSENSOR DEMONSTRATION FLIGHTS AROUND THE SOUTHERN COAST OF NEWFOUNDLAND

ABSTRACT Several oil spill remote sensing flights were conducted by Environment Canada off the Southern coast of Newfoundland, Canada in late February, early March 2004. These flights were undertaken to demonstrate the capabilities of the Scanning Laser Environmental Airborne Fluorosensor (SLEAF) in real-life situations in the North Atlantic and Newfoundland coastal regions in late winter weather conditions. Geo-referenced infrared, ultraviolet, color video and digital still imagery was collected along with the laser fluorosensor data. Brief testing of a Generation III night vision camera was also conducted. Flights were conducted in the shipping lanes around the Newfoundland coast, out to the Hibernia and Terra Nova oil platforms and over known oil seep areas. Details of the analysis of laser fluorescence data collected during these flights will be presented along with a summary of the remote sensing flights.

AIRBORNE OIL SPILL SENSOR TESTING: PROGRESS AND RECENT DEVELOPMENTS

ABSTRACT It is now possible to measure the thickness of an oil slick on water by remote sensing. A laboratory sensor has been developed to provide this absolute oil slick thickness measurement. A joint project between Environment Canada, U.S. Minerals Management Service (MMS), Imperial Oil Research Ltd., and Industrial Materials Institute of the National Research Council of Canada has led to the development of a prototype slick thickness measurement system, known as the Laser Ultrasonic Remote Sensing of Oil Thickness (LURSOT) sensor. This prototype was the first step in achieving the ultimate goal of providing an airborne sensor for the remote measurement of oil slick thickness on water. The LURSOT sensor employs three lasers to produce and measure the time-of-flight of ultrasonic waves in oil, hence providing a direct measurement of oil slick thickness. The successful application of this technology to the measurement of oil slick thickness will benefit (1) the scientific community as a whole by providing information about the dynamics of oil slick spreading and (2) the spill responder by providing a measurement of the effectiveness of spill countermeasures such as dispersant application. The first part of this paper provides initial results from laboratory testing prior to a second round of airborne test flights of the modified LURSOT system. The second part of this paper provides details on a new generation of laser fluorosensor, known as Scanning Laser Environmental Airborne Fluorosensor (SLEAF). SLEAF recently has been installed on Environment Canada's DCS aircraft. SLEAF incorporates a high-power excimer laser, high-resolution range-gated intensified diode-array spectrometer, and a pair of variable speed and angular displacement scanning mirrors. These scanning mirrors provide SLEAF with the across-track sampling pattern needed to detect narrow bands of oil that can pile up along the high tide lines of beaches and shorelines. Ground testing of SLEAF has now been underway for some time. This paper provides details of the sensor installation and testing program, and illustrates the operational capabilities of the new system. It is believed that this new sensor will provide prompt reliable detection and mapping of oil contamination in a variety of marine and terrestrial environments.

Initial Testing and Integration of The Scanning Laser Environmental Airborne Fluorosensor

ABSTRACT The intended role of the scanning laser environmental airborne fluorosensor (SLEAF) is to detect and map oil and related petroleum products in complex marine and shoreline environments. To improve on the small footprint and nadir-looking geometry of the previous generation laser fluorosensor, the LEAF, a conical scanning mirror was included to provide the broad cross-track and along-track sampling required to detect oil in these complex environments. Laser fluorosensors have the ability to confirm or reject suspected oil contamination sites that have been targeted by other “nonspecific sensors” such as infrared, ultraviolet or visible cameras. This confirmation will free response crews from the labourious task of physically inspecting each site, and direct crews to sites that require immediate remediation. The construction of the SLEAF system was recently completed. Following integration of the various components of the system, a systematic verification of SLEAF system functionality was initiated. The ability of the SLEAF to detect, classify, and estimate oil coverage was tested and verified. In total, 21 oils ranging from light refined, crude through to heavy refined oils were examined. The API gravities of the oils examined varied from 11.9 to 48.6, while the aromatic content varied between 13 and 52%. The SLEAF system is presently being integrated into Environment Canada's DC-3 aircraft and will undergo extensive testing to confirm its functionality in an airborne environment. This paper will report on progress with the installation of the SLEAF system.

TURNING OVER A NEW LEAF: THE NEXT GENERATION OF LASER FLUOROSENSORS

ABSTRACT Detecting oil in the marine environment with remote sensing is difficult at the best of times. When that environment includes ice, kelp or seaweed, and the myriad substrates found on beaches and shorelines, the detection becomes increasingly difficult. The laser fluorosensor is the only sensor that detects a primary characteristic of petroleum products, namely, their unique fluorescence spectral signatures. A laser fluorosensor reliably detects oil on ice in ice-infested waters, among floating kelp and seaweed beds, and on complex beach and land environments. This paper will provide details of the Scanning Laser Environmental Airborne Fluorosensor (SLEAF) and the anticipated benefits of the SLEAF system to the oil spill response community.

Recovery of the Irving Whale oil barge: Overflights with the laser environmental airborne fluorosensor

In the summer of 1996 the oil barge, Irving Whale, was successfully raised from the depths of the St Lawrence River with the majority of its cargo of bunker C fuel oil intact. As part of the recovery effort, the Emergencies Science Division of Environment Canada performed airborne remote sensing flights over the site of the barge prior to, during and following the lift procedure. The primary sensor employed during these remote sensing flights was the laser environmental airborne fluorosensor (LEAF). Additional equipment on board Environment Canada's DC-3 aircraft included an RC-10 colour mapping camera and two down-looking video cameras. In the days leading up to the lifting of the Irving Whale, the LEAF system detected bunker C fuel oil on the surface of the gulf in close proximity to the location of the sunken barge. This oil was believed to have been dislodged from beneath structures on the top of the barge during inspections, welding and other preparations in advance of the lift. On the actual day of the lift, 30 July, greatly increased amounts of bunker fuel were detected. During each overflight, the real-time LEAF system produced timely, concise map-based oil contamination information in hard-copy form. The locations of the visibly thick and recoverable oil were radioed to spill response personnel on the surface and promptly recovered by booming and skimming operations. In addition, the LEAF system found extremely thin, sub-sheen levels of oil over the majority of the southern Gulf of St Lawrence on the day of the lift. The extent of this coverage was greatly reduced the following day (presumably due to further spreading) and essentially eliminated by 1 August. The LEAF system on the DC-3 continued to monitor the Irving Whale as it was transported to Halifax, Nova Scotia on the deck of the submersible vessel Boabarge 10. During transit no oil which could be attributed to the Irving Whale was detected, apart from a small residual amount at the lift site.

Laser fluorosensor overflights of the Santa Barbara oil seeps

The Emergencies Science Division of Environment Canada recently participated in a series of remote sensing flights over the naturally occurring oil seeps off Santa Barbara, California. During these flights the laser environmental airborne fluorosensor was operated to test its ability to detect oil in an actual marine environment. This joint project was sponsored by the United States Minerals Management Service and the Emergencies Science Division of Environment Canada. The Santa Barbara area of the California coastline contains numerous gas and petroleum deposits, which are slowly released from faults under the water and rise to the surface in the form of gas, oil and tar. In and around several of these seeps are kelp beds that release biogenic material, which can be mistaken for petroleum oil by certain remote sensors and human observers. This biogenic oil does not fluoresce when irradiated with ultraviolet light since it contains none of the aromatic compounds necessary to absorb the ultraviolet light and return fluorescence. The laser environmental airborne fluorosensor is, therefore, able to discriminate between this non-fluorescing oil and petroleum oils, which fluoresce with characteristic spectral signatures and intensities. High-resolution colour reconnaissance camera images and down-looking video images were collected concurrently with the fluorescence data for documentation purposes. Fluorescence data were collected at 100 Hz and correlated in real-time against reference spectra characteristic of light refined, crude and heavy oils. Maps of oil detection locations were produced in flight and printed in the aircraft. This paper will present details of the overflights and post-flight analysis of the fluorescence data using the Pearson correlation coefficient.

Physiological responses of Rhizophora mangle to oil spills: Possible recovery on transplantation

In the summer of 1996 the oil barge, Irving Whale, was successfully raised from the depths of the St Lawrence River with the majority of its cargo of bunker C fuel oil intact. As part of the recovery effort, the Emergencies Science Division of Environment Canada performed airborne remote sensing flights over the site of the barge prior to, during and following the lift procedure. The primary sensor employed during these remote sensing flights was the laser environmental airborne fluorosensor (LEAF). Additional equipment on board Environment Canada's DC-3 aircraft included an RC-10 colour mapping camera and two down-looking video cameras.In the days leading up to the lifting of the Irving Whale, the LEAF system detected bunker C fuel oil on the surface of the gulf in close proximity to the location of the sunken barge. This oil was believed to have been dislodged from beneath structures on the top of the barge during inspections, welding and other preparations in advance of the lift. On the actual day of the lift, 30 July, greatly increased amounts of bunker fuel were detected. During each overflight, the real-time LEAF system produced timely, concise map-based oil contamination information in hard-copy form. The locations of the visibly thick and recoverable oil were radioed to spill response personnel on the surface and promptly recovered by booming and skimming operations. In addition, the LEAF system found extremely thin, sub-sheen levels of oil over the majority of the southern Gulf of St Lawrence on the day of the lift. The extent of this coverage was greatly reduced the following day (presumably due to further spreading) and essentially eliminated by 1 August. The LEAF system on the DC-3 continued to monitor the Irving Whale as it was transported to Halifax, Nova Scotia on the deck of the submersible vessel Boabarge 10. During transit no oil which could be attributed to the Irving Whale was detected, apart from a small residual amount at the lift site.

Depth resolved detection of oceanographic variables in the St. Lawrence estuary using a laser fluorosensor: instrument characteristics and first results†

Abstract A 64-channel Laser Environmental Airborne Fluorosensor (LEAF) system for sea surface oil detection was modified for continuous depth-resolved detection of gelbstolT and chlorophyll a spectral fluorescence, and water Raman scattering. The system was successfully tested during shipborne and airborne experiments in the St. Lawrence Estuary. System performance was studied, and the best integration time to optimize the signal to noise ratio (S/N) was determined using dilTerent statistical procedures such as the geophysical and robust statistical methods. In general, raw data indicated S/N of about 150, 10, and 4 for Raman. gelbstolT and chlorophyll a signals, respectively. Results with calibrated LEAF spectra clearly indicated that, with this system, water Raman scattering, geibstolT and chlorophyll a signals could be detected down to a maximum depth of 4·8 m. Spatial distribution of these quantities compared well with simultaneously observed ill Silll structure of oceanographic variables, such as, underwater light attenuation, salinity and chlorophyll a fluorescence. In the perspective of modelling primary production in coastal and estuarine waters in the St. Lawrence system (Case II waters), the utilization of LEAF should provide an adequate representation of the spatial and temporal variation pattern of oceanographic variables, at scales between those from ships and satellites.