Lectures Given at Agu, April 20, 1966, Variations in Sound Velocity Profiles in the Ocean Between Bermuda and the Antilles. Detection of Internal Waves from Doppler Shift Observations

摘要

Spatial and temporal variations in the sound velocity structure over the broad ocean between Bermuda and the Antilles were revealed by comparison of numerous measurements made in the summer of 1962 and 1964. From the 1964 measurements, the geographic variations in the contours of equal sound velocity for a constant depth within the main thermocline region reveal a spatial pattern having an average wave length of 240 miles. The variations are believed to be evidence of the interference between long Rossby waves incident upon and reflected from the bank of the Bahamas Platform. In April 1965 a cruise of the R/V CHAIN was undertaken to determine whether or not internal waves were generated by the thermal front region located 120 miles southwest of Bermuda. It was conjectured that internal waves generated at the thermal front could be detected by the Doppler shift observed in the wave fluctuations measured relative to a moving ship towing a sensor. Evidence will be presented showing a marked Doppler shift in the frontal region at 6 knots. The Doppler shift observations indicate that the phase of the waves advance toward the frontal region. It appears as though the frontal region is a sink for internal waves; however, it may be a region of sources and sinks. (Author)