Fluctuations 



141 



IRREGULAR FLUCTUATIONS IN TRANSPORT OF 

 THE FLORIDA CURRENT 



The most spectacular fluctuations of the Florida Current are to be seen in 

 the periods of extraordinary flow revealed by the submarine-cable measure- 

 ments throughout the months of December, 1952, and January and April, 

 1953 (fig. 73). During these months the Florida Current maintained a flow 

 of about 8 X 10^ m.^/sec. in excess of its normal flow. Mr Jerome Namias 



Fig. 73. Comparison of high-flow regimes ia the Florida Current, as obtained 

 from the submarine -cable measurements (curve A), with those computed from 

 the five-day mean zonal pressure difference between 30 and 20° N. (curve B). 

 The upper curve (A ) shows excess of flow above mean flow. 



suggested to me that these periods of excessive flow might be associated 

 with thirty-day persistent breakdowns of the North Atlantic wind circula- 

 tion. After a number of trial analyses of weather maps, I decided to use 

 the five-day mean pressure difference between 30 and 20° N., averaged all 

 across the ocean, as an index of the strength of the trades north of the 

 West Indies. These five-day mean zonal pressure differences (30° minus 20°) 

 are plotted in fig. 73. 



It is clear that there are three sustained periods of breakdown of the 

 Bermuda-Azores high, and that invariably they precede the periods of 



