MULTISPECTRAL REMOTE-SENSING AND TRUTH DATA FROM THE TENYO-MARU OIL-SPILL

On 22 July 1991, the Tenyo Maru sank in 87 fathoms of water off Cape F lattery, Washington following a collision with the grain ship Tou Hai. The initial spill included approximately 100,000 gallons of the bunke r oil and diesel fuel carried by the Tenyo Maru. Oil continued to be r eleased at a rote of approximately 500 gallons per day during the subs equent weeks. Sea-truth and remote sensing data were collected in the vicinity of the wreck site during the period 5-10 August 1991. Oil con tent in samples representing 150 cm2 of ocean surface typically ranged from undetectable to 180 mg. Most samples contained 5 mg of oil or le ss, indicating an oil film less than 0.5 micrometres thick at these lo cations. Chemical analysis of samples identified two unique oils in th e slick, one containing enhanced concentrations of toxic PAH. The remo te sensing data revealed variability in oil thickness, particularly th rough the ultraviolet and long-wave infrared bands and, secondarily, i n other visible and near-infrared bands. Processing is described to re move atmospheric effects from the remote sensing data and combine ultr aviolet and infrared band data into a single intuitive display. A mid- wave infrared band showed no useful signature for the oils present at Neah Bay. No microwave signature was observed due to the small oil amo unts.