52 



Hydrography of the Stream 



obtained from the Multiple Ship Survey of 1950. This was the most de- 

 tailed cruise ever made. Seven ships were employed. The time sequence of 

 meander patterns was observed. 



According to the analysis by FugUster and Worthington, two meanders 

 in the western half of the surveyed region moved eastward at a rate of 

 about 1 1 nautical miles a day. The water in the smftest part of the Stream 

 itself moves more than a hundred miles a day. The amplitude of the 

 meanders nearly doubled in two weeks. Fig. 29 shows the mean tem- 



Fig. 28. Positions of the maximum cross-current temperature gradients at 

 a depth of 100 m., from all surveys in the period 1946-1950, according to 

 Fuglister and Worthington (1951, fig. 4). 



perature, in degrees Fahrenheit, of the upper 200 m. layer of the western 

 part of the survey area at the beginning of the period of observation. 



In the eastern half of the surveyed area a very much distorted meander 

 was observed to break ofiF into a clearly defined eddy. Fig. 30 shows the 

 position of this eddy on June 17. The existence of eddies had been inferred 

 before, but this one was very closely studied because so many ships were 

 in the area. 



Fig. 31 shows a survey of the 'edge' of the Gulf Stream as determined 

 from a single airplane flight, by means of the air-borne radiation thermo- 

 meter (Stommel et al., 1953). The black dots indicate the position of 

 crossing of a strong surface temperature discontinuity as observed from 



