Acoustic imaging through sea ice

We use marine transducers to determine whether acoustic methods are practical to identify the presence of crude oil trapped beneath sea ice. Here we present the modeled results and compare the theoretical response to a field test conducted in March, 2006. There is a clear contrast in acoustic velocity values between typical sea ice, average density crude oil, and salt water near freezing temperatures. Our selected field results match the expected response for amplitude and travel time values, however to obtain a clear signal from the ice/fluid interface and sea bed, we must alter the ice surface. In situ sea ice conditions often consist of a layer of snow and/or trapped air above the solid ice surface. We removed this layer and coated the ice surface with a thin layer of sea ice. Once prepared, we obtained consistent reflections from the ice/oil, ice/water, and water/sea bed interfaces.