Hydrography of the Stream 67 



origins of various parts of the Stream, but in order to refine the method 

 it would be necessary to have some quantitative information about mixing, 

 and it would be necessary to make more widespread and frequent hydro- 

 graphic sections than are now available. This would require great expense 

 and effort with present techniques. In addition, the uncertainty about the 

 choice of the reference level makes transport calculations rather fuzzy. 

 Thus, in a few words, sparsity of data, ignorance of mixing, and uncertain 

 transport computations conspire to maintain the technique of water-mass 

 analysis at a qualitative rather than a quantitative level. 



Although the hope that we shall ever have really frequent and wide- 

 spread hydrographic data is very dim, there is a need for repeating certain 

 hydrographic stations made in the past. With the waning popularity of the 

 hydrographic station there has been a tendency toward slovenHness in the 

 work which makes some of the new data worthless for water-mass analysis. 

 In order to offset this tendency, as well as to gather new precise data on 

 possible secular changes in the properties of the deep waters, Worthington 

 began, in 1954, to rerun all the old Atlantis sections of twenty-odd years 

 ago. This tedious and very demanding work, requiring precision measure- 

 ments under difficult environmental conditions, is now half finished. When 

 completed, it will be a useful step toward a firm and secure beginning for 

 a long-term study of slow chmatic changes of the ocean. 



Just as Iselin (1936) used the salinity minimum at the depth of 700 m. 

 to trace water masses in the Gulf Stream, Richards and Redfield (1955) 

 have recently used dissolved-oxygen deficiency to attempt to trace water 

 at about 200 m. It is known that the waters from the Straits of Florida 

 (at 200 m.) are more deficient in dissolved oxygen than are the waters 

 that join the Stream north of the Indies. A diagram analogous to the T-S 

 diagram is used, but the coordinates are dissolved-oxygen concentration 

 and Cj. The results of Richards and Redfield's analysis of eight available 

 Gulf Stream cross sections made within the period 1950-1953 were highly 

 variable; that is, the amount and position of Florida Straits water at 

 200 m. present in the Gulf Stream varied greatly from section to section. 

 Of course, eight sections are too few from which to estabhsh the nature of 

 the variability and to relate it to any continuously measured quantity 

 such as variation in difference of sea level across the Straits; but it is 

 certainly worth while to demonstrate the fact of variability itself. The 

 study also showed that there are separate filaments of the Florida Straits 

 type of water in the counter current to the right of the current. Possibly 

 this has some bearing on the question whether the countercurrent is 

 frictionally (p. 97) or advectively (p. 123) produced. 



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