Presentation
Effect of Water and Air Temperature and Light Levels on Thermal Sensing of Oil Slick Thickness
DescriptionResponse decisions and natural resource damage assessment (NRDA) claims are often aided by knowing the thickness of spilled oil floating on water. For example, knowing the thickness can impact the type of clean up device used to remove slicks or be important in deciding the potential extent of damage to sensitive species that are directly exposed to oil. This kind of information is needed with fine spatial resolution that many remote sensing platforms cannot provide. Thermal sensors have been used to measure thickness of oil in several spills (e.g., Huntington Beach, CA). Recent research funding from the Canadian Multi-Partner Initiative (CAMPRI), the US Coast Guard to NOAA’s Office of Response and Restoration (ORR), and the Coastal Response Research Center ((CRRC) has enabled our team to determine the efficacy of thermal sensors suspended on an uncrewed aerial system (UAS) to determine oil thickness with < 10% relative standard deviation (%RSD) in cold climates provided thickness is in the range of 50 to 1,000 µm for crude oil. Diesel oil is also detectable, but the %RSD is higher, and the lower range is reduced. Tote tests conducted by the team at the: Cold Regions Research and Engineering Laboratory (CRREL, Hanover NH), Sandia Laboratory facility in Oliktok, AK, and at USCG Great Lakes Center for Expertise (Sault Ste Marie, MI) all indicated that there is a hyperbolic relationship of increasing apparent temperature of oil as thickness increases to an asymptote at about 1,000 µm in water > 32 °F. The Oil Spill Recovery Institute provided funding to explore the impact of ambient light levels (lux), and air and water temperature on these relationships over 24 hr periods for totes containing HOOPS oil, diesel, and ice (0 and 50%). Because this research was conducted in March in New Hampshire, light levels varied between 0 and >90,000 lux depending on the time of day/night and the percent cloud cover. Water and air temperatures were somewhat related to time of day and weather, as well as presence of ice and ranged from below freezing to > 55 °F. In the early morning before sunrise, the apparent temperatures of thicker oil slicks were often below those of thinner ones, creating an inverse (decreasing) hyperbolic relationship. Once the light levels increased after daybreak, even with cloud cover, the relationships reverted to the increasing hyperbolic relationship. These results suggested that use of thermal sensors to determine oil thickness in cold waters may be only possible during daylight and not immediately adjacent to ice.
Event Type
Paper
TimeThursday, May 16th11:00am - 11:20am CDT
Location298-299
Remediation