SHORT-PERIOD VERTICAL DISPLACEMENTS OF THE UPPER LAYERS IN THE STRAIT OF GIBRALTAR. PART I. TEXT
Abstract
As a background to this subject, a brief description of the hydrology and the long-term vertical displacements of the surface layers is first presented. This is based on observations made by various authors prior to 1957 and by three expeditions organised by the NATO Sub-Committee on Oceanography in the summer periods of 1958, 1960, and 1961. The principal part of the report is based on observations of short-term displacements made by the author in the summer periods of 1958, 1959, and 1961, using primarily the Woods Hole Oceanographic Institution's termistor chain. These thermistor chain records revealed independent trains of internal waves superimposed on each of the semidiurnal waves of the tidal period. It was found that these waves had amplitudes varying from 40 m to 120 m, wave lengths from 200 m to 1500 m, and periods from 10 to 40 minutes. The length of each train averaged 4 1/2 miles from leading to trailing wave, each wave being slightly lower than the one before. The waves generally formed over the submarine sill that lies west of Tarifa and moved eastwards into the Mediterranean at speeds that increased up to a value of 5 knots by the time they had travelled 16 miles. They were found to have vanished completely within a distance of 50 miles (i.e., 30 miles east of the Rock).
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1964
- Accession Number
- AD0808764
Entities
People
- R. Frassetto
Organizations
- SACLANT ASW Research Centre