Development of the fetch-limited directional wave spectrum

The Surface Contour Radar (SCR) is a 36 GHz computer-controlled airborne radar which generates a false-color coded elevation map of the sea surface below the aircraft in real-time. After the data has been collected, non-real-time programs remove the aircraft motion through the use of accelerometer data and apply a two-dimensional FFT to produce directional wave spectra. This system has been used to map the evolution of the fetch-limited directional wave spectrum off the eastern seaboard. The flight lines were displaced both north and south of the Delaware Bay following the passing of a weather front. Analysis indicates that, in addition to the waves aligned with the wind direction which grow with increasing fetch, there are other off-shore wave components whose directions significantly differ from the wind direction, and whose origin seems to be the mouth of the Delaware Bay.