538 



Currents in a Strait 



18 20 22 2 

 8X1921 9X 



8 10 12 14 16 18 20 22 2 



lOX 



Time, hr 



152 



15-0 



MB 



146 



144 



142 o 



140 



138 



136 



134 



132 



13 

 128 



o 



4 6 



Fig. 249. Strait of Gibraltar: periodic oscillations in the mean salinity and mean tempera- 

 ture of the layer 100-200 m according to the observations of the "Dana" St. 1138 (5° 30' W.) 



(according to Schott). 



Table 144. Tidal current and periodic variations in temperature and salinity 



in the Strait of Bab el Mandeb aMOO m depth 



(Five semi-diurnal moon peroids) 



* minimum; t maximum. 



oscillation in the sea surface slope as 10 cm in a model of the Strait of Gibraltar between 

 Tarifa and Gibraltar, gave an internal boundary oscillation with tidal period and 

 amplitude of 110 m which is in agreement with the order of magnitude of the observed 

 values. Strong well-developed internal tide waves were also found at the 15-day 

 anchor station in the Strait of Messina. This case is of particular interest because the 

 wave here reaches the limits of stability characteristic for such waves and at times even 

 exceeds it (see Vol. II). 



5. Processes in Estuaries (River Mouths) 



River water flowing into the sea gives rise to compensation currents along the river 

 bed, which show similarities to current processes in sea straits. Ekman (1876) in an 



