Accession Number : AD0856028

Title :   Spatial Observations of Internal Waves in the Strait of Gibraltar.

Descriptive Note : Technical rept.,

Corporate Author : SACLANT ASW RESEARCH CENTRE LA SPEZIA (ITALY)

Personal Author(s) : Ziegenbein, Joachim

Report Date : 15 JUN 1969

Pagination or Media Count : 38

Abstract : The results of observations made on internal waves in the Strait of Gibraltar in September-October 1968 are described. Sets of internal waves with periods of around 15 minutes and amplitudes of around 15 m were simultaneously recorded on two buoys moored 2 miles apart. In some cases, while moving from west to east, the amplitudes of the waves were found to increase two to six times, whereas no change in frequency could be observed. In addition to the oscillatory-type internal waves, singulary waves, i.e. isolated depressions of only the isotherms, were detected. An attempt to obtain some information on the hydrodynamic stability, revealed a Richardson number of the order of 1-10 at the time that internal waves were occurring. The propagation speed of the corresponding features passing from one buoy to the other was about 4 knots. Comparison with similar measurements made in 1967 shows a remarkable difference in amplitude and regularity of the events, the reasons for which are not clear. (Author)

Descriptors :   (*WATER WAVES, GIBRALTAR STRAIT), (*OCEAN WAVES, GIBRALTAR STRAIT), FREQUENCY, HYDRODYNAMICS, BUOYS, OCEAN CURRENTS, RECORDING SYSTEMS, THERMISTORS, TIDES, OSCILLATION, MAPPING, TEMPERATURE, DENSITY, ANTISUBMARINE WARFARE, THERMOCLINES.

Subject Categories : Physical and Dynamic Oceanography
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE