251 



The stream function field which corresponds to the current transport 

 chart in Figure 5 (06 GMT 1 February 1965) is shovn in Figure 6. Current 

 vectors have been plotted at selected gird points to show the degree of fit. 

 The fact that the derived stream function is nondivergent while there is 

 divergence in the initial velocity field explains some of the cross-contour 

 flow. In general, however, this appears to be small in most places, and the 

 stream field provides a good representation of the current pattern. 



It is interesting to note that the stream function analysis shows close 

 correlation to the large-scale SST analysis shown in Figure 3. As one 

 should expect, thermohaline considerations (as influenced by the semipermanent 

 circulation of the atmosphere) determine the large-scale current pattern while 

 mass transport by wind and waves contributes toward smaller scale details . 



A good example of the latter effect can be seen to the northeast of 

 Hawaii . A strong, quasi-stationary cyclone has completely disrupted the 

 normal west-east extension of the Japanese current. To a lesser degree, the 

 same thing is happening off the west coast of France; the typical northwesterly 

 current has been replaced by flow from the southeast. 



D. ADVECTIVE TEMPERATURE CHANGES 



From the computed currents one can determine the change in SST which 

 would be due to advection alone. Since the "permanent" or thermohaline 

 component would be nearly along the sea surface isotherms, the advective 

 patterns should result primarily from atmospheric driving forces of synoptic 

 scale. Figure 7a- shows the results of advecting the SST pattern with the current 

 field shown in Figures 5 and. 6. Areas of cold advection are stippled with 

 heavier shading used to denote advection of greater than about O.IF per 

 2U hours . Weak warm advection is indicated by lack of shading while warm 

 advection stronger than O.IF per 2^4- hours is shown by cross-hatching. 



Figure 7b represents the actual difference between the SST analyses 

 from 12 GMT 1 February and 12 GMT 31 January 1965. As can be seen, the cor- 

 respondence in some parts (particularly in the vicinity of strong storms 

 near Hawaii, Newfoundland and the Azores) is fairly good. In other areas 

 the signs are clearly opposite . One can only conclude that advection plays 

 an important role in some areas and is completely outweighed by heat exchange 

 effects in other areas. Namaias (1959) and Eber (1961) came to about the 

 same conclusion. The maximum advection computed in this case was 0.85°F per 

 2.k hours which agrees with earlier findings of Laevastu (i960). 



5. THE FNWF SCHEME FOR SUBSURFACE THERMAL STRUCTURE ANALYSIS AND 



PREDICTION 



Figure 8 is a further breakdown of the master scheme discussed in 

 section 3. As can be seen, all of the computational programs described in 

 the preceding section enter into the determination of thermal structure with 



