Please join us for the following AOS Seminar this Thursday, November 21 at 4:00pm in Spiess Hall 330:
Speaker: Sean Walstead, Scripps Institution of Oceanography
Title: "Forward scattering of surface reflected underwater sound: measurements, predictions, and applications"
Abstract: Forward scattered data is presented from both paddle-driven and wind-driven wave tank experiments and from the Surface Processes and Communications Experiment (SPACE08). These experiments show that during particular conditions, the ocean surface can act like a lens, generating focused acoustic arrivals that in some cases may equal or exceed the intensity of the direct arrival regardless of acoustic transmission frequency. The amplitude and phase of acoustic energy reflected from the sea surface depend sensitively on the elevation and local curvature of the surface near specular reflection points. This raises the interesting possibility of using the structure of the reflected sound to reconstruct the surface shape, which is a main focus of this talk. The goal of the inversion work is to apply the process to waves in the open ocean. In moving forward with that idea, predictions about surface scattering losses such as out of plane scattering are made by analyzing simulated 2-D Pierson-Moskowitz sea surface elevation profiles. Some preliminary inversion results are also presented from the SPACE08 experiment.