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RECORDS OF OBSERVATIONS, SCRIPPS INSTITUTION OF OCEANOGRAPHY 



Owing to the complexity of the pattern one 

 can evidently not expect to find a repetition of 

 identical conditions each year. Examination of 

 the charts of the distribution of temperature 

 and salinity at the surface, at 50, and 200 met- 

 ers, and of the dissolved oxygen at 200 meters 

 shows, however, that the general pattern is the 

 same for all cruises although the absolute values 

 vary. Therefore, emphasis can be placed on the 

 maximum and minimum values contained in table 2. 

 The location of the stations indicated in this 

 table can be found in figure 1 in the introduc- 

 tion to this report (facing page l). 



It follows from the foregoing discussion that 

 the area covered by these investigations may be 

 roughly divided into three zones: First, the 

 Offshore Zone, where there is generally a flow 

 toward the south or southeast. In this area the 

 surface temperatures are, as a rule, relatively 

 high and the salinities low, and the convection 

 layer is thick. Second, the Trough Zone, ex- 

 tending south and east from the area north of 

 Point Conception. This represents the zone sepa- 

 rating the southeasterly flow from the Counter 

 Current flowing toward the north. Within this 

 zone upwelling, particularly diiring the spring 

 and summer months, maintains low temperatures 

 and relatively high salinities in the surface 

 layers, and the convection layer is thin. Third, 

 the Counter Current or Coastal Zone, where there 

 is flow either toward the north or, close to the 

 shore, toward the south. Except in winter this 

 zone does not extend farther north than Point 

 Conception and in spring it may be entirely lack- 

 ing. In this zone the surface temperatures are 

 again relatively high and the salinities are in- 

 termediate between those of the other two zones. 

 The convection layer is usually rather thin. 



It will be seen that these zones are not geo- 

 graphical but that they depend upon the pattern 

 of flow. Consequently, individual locations may 

 be under the regime of different zones at dif- 

 ferent times of the year. However, on the basis 

 of this division into zones, a fair estimate of 

 the distribution of conditions can be derived 

 from the pattern of flow. On the other hand, if 

 the temperature distribution in the upper layers, 

 say, down to a depth of 100 meters, is known, a 

 very good idea of the pattern of circulation can 

 be obtained. 



In conclusion, some suggestions are presented 

 with respect to the possible character of the 

 annual changes of the currents off the coast. 

 The fact that the Counter Current is most con- 

 spicuous in winter when the winds are variable 

 indicates perhaps that the inshore flow to the 

 north represents a "normal" state which is de- 

 vfeloped in the absence of strong external influ- 

 ences. Perhaps the Counter Current, which, in 

 winter, can be traced all along the coast of 

 California, represents a counterpart to the in- 

 shore flow to the southeast along the east coast 

 of the United States, on the left-hand side of 

 the Gulf Stream. If this assumption is correct, 

 the prevailing northwest winds in spring and 

 early summer bring about "abnormal" conditions 

 which are caused by the upwelling along the coast. 

 When the external influence of the wind decreases, 

 large eddies develop (fig. 4), but gradually the 

 "normal" state is reestablished. 



The fact that below 200 meters the Counter 

 Current appears to be equally well developed in 

 all seasons perhaps supports the conclusion that 

 the Counter Current represents a "normal" feature 

 which in the upper layer is disturbed by the pre- 

 vailing winds of the spring and early summer. 



