Basic Principles of the General Oceanic Circulation 561 



nautical miles in 24 h with up to 80-100 nautical miles in the current core. These 

 values correspond to about 1 •5-2-5 m/sec which is hardly reached even in the down- 

 stream parts of big rivers. According to Krummel (1911, p. 576), the axis of the stream 

 under steady conditions is: 



35 nautical miles in the Yucatan Channel (east of Contoy Island), 



25 nautical miles north of Havana (85° W.), 



11 nautical miles east of Fowey Rocks (Florida 25-7° N.), 



19 nautical miles east of the Jupiter light tower (Florida 27° N.), 



38 nautical miles south-east of Cape Hatteras. 



At the edges, particularly on the western side, the current shows often variations in 

 direction and strength. Not infrequently there is a counter current flowing in a south- 

 westerly or westerly direction along the Florida Keys into the Gulf of Mexico and is 

 well separated from the basic Gulf Stream. It is connected with the counter current 

 always found further north off the east coast of America. In the most narrow parts 

 of the channel the current has a width of about 30 nautical miles, off Cape Canaveral 

 (28-5° N.) about 60 and off Charleston a width of as much as 120 to 150 nautical 

 miles. In general, the western border of the blue coloured warm water of the current 

 follows the continental slope. To the west of it on the shelf the cold green water of the 

 "cold wall" is usually travelling slowly to the south; (see Pt. I, p. 144, Fig. 60). The 

 Florida Current is joined here by the important Antilles Current flowing north-west 

 to the north of the Bahamas. Before the junction (27° N.) it is narrowed in the con- 

 vergence region of the Sargasso Sea, whereby it becomes of some importance (see 

 Nielsen, 1925; Wiisx, 924). North of Cape Hatteras the Gulf Stream turns farther 

 and farther away from the continental slope, possibly due to offshore winds, Coriolis 

 influence and the increasingly strong cold coastal current of low salinity. This is the 

 beginning of the second part of the Gulf Stream. Its left-hand boundary remains 

 sharply separated from the coastal waters but the right-hand edge is extremely blurred. 

 Here, due to the deflection of the stream lines a counter current is formed which, 

 although narrow, weak and variable is a characteristic phenomenon of the eastern 

 flank of the main current, but because of its narrowness it can rarely be detected by 

 means of ship displacements ; however, the farther to the north-east the stronger and 

 more frequent this current appears. Only mean positions of the current can be deduced 

 by evaluation of the average physical conditions at the sea surface. Better results can 

 be obtained by systematic recordings of the sea-surface temperature at short time 

 intervals ; these then give a more accurate indication of the mean position of the warm 

 Gulf Stream core and also of its northern and southern limit (see Pt. I, p. 144, also 

 FuGLiSTER, 1947). Determinations of the Gulf Stream position obtained by different 

 methods can be combined to give an average picture (Neumann and Schumacher, 

 1944) but it should always be borne in mind that the boundaries of the warm- water 

 belt cannot necessarily be regarded as identical with the boundaries of the current. 



From about 55° W. the left side of the Gulf Stream is flanked by the cold and weakly 

 saline water of the Labrador Current. At this polar front the cold water masses sink 

 below those of the Gulf Stream and thereby numerous vortices are formed. To the 

 south of the Newfoundland Banks the Gulf Stream turns sharply towards the south 

 (p. 421) and again back towards north and from here gradually widens and splits into 



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