Tidal-Induced Pulses in the Flow through the Strait of Gibraltar
NAVAL OCEAN RESEARCH AND DEVELOPMENT ACTIVITY STENNIS SPACE CENTER MS
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Data collected in the 1960s and recent data indicate that the flow in the Strait of Gibraltar does not move in the form of continuous currents but as tidal-induced pulses. A descriptive model based on these data indicates that the pulses are a result of increases in the speed of the tidal streams as they encounter the constrictions of the regional bathymetry especially the Camarinal Sill and between the Camarinal Sill and Tarifa. Periodic increases modify the regional flow so that during each tidal cycle, the eastward-flowing surface Atlantic water and westward-flowing deep Mediterranean water are alternately emitted as large pulses in the Mediterranean Sea Atlantic water and Atlantic Ocean Mediterranean water. These periodic pulses vary in the amount of water they contain according to the daily and monthly variation in tidal current strength. Besides the pulses generated at the intervals of the semidiurnal tide, it appears that short-period pulses of flow are generated on the Camarinal Sill. Occurring near the time of the greatest local variations of the tidal current, these short-period pulses are able to trigger very strong internal waves and current fronts in the upper layer, which are propagated eastward into the Alboran Sea. These continuous periodic pulses are a permanent feature of the waters of the Strait of Gibraltar that should be taken into account in any study of the region. Reprints.
- Physical and Dynamic Oceanography