distribution of properties at OWS-V have some order 

 and permit identification and isolation of different proc- 

 esses that contribute to changes in the distributions. 

 This point is illustrated by the time-series sections of 

 salinity versus a, (Fig. 14). At depths greater than a, 26 

 the T-S relationships remain relatively constant with 

 the salinity minimum occurring at a constant tr, level, <t, 

 26.8. 



Variations in the depth of sigma-( below (T, 26 (Fig. 14) 

 reflect changes in the baroclinicity of the area. Deepen- 

 ing of the pycnocline as indicated by the depth of a, 26 is 

 associated with an increase in the surface salinity during 

 winter or the appearance of a shallow subsurface salinity 

 maximum at other times of the year. A shallow subsur- 

 face salinity maximum is characteristic of the Kuroshio 

 Current. Meridional sections near OWS-V show the pyc- 

 nocline depth to increase southward. Thus, the associ- 

 ated changes in the salinity of the upper layers above a, 

 26 indicate meandering of the Kuroshio Extension. 



The net heat loss across the sea surface at OWS-V 

 during the fall and winter 1967-68 was anomalously high 

 and during 1968-69 anomalously low. These anomalies 

 were not reflected in changes of the heat content in the 

 layer above a, 26. In fact, changes in the thickness of the 

 layer are the dominant influence in changes of heat con- 

 tent, obscuring effects of the seasonal variation of the 

 heat exchange across the sea surface. The variation of 

 the heat content of the layer due to a change in the mean 

 temperature (Fig. 17) does reflect the seasonal variation 

 of heat exchange across the sea surface. Again, however, 

 the anomalous heat loss during 1967-68 and 1968-69 are 

 n )t reflected in anomalous declines of the mean 

 temperature of the upper layer. Anomalously low 

 temperatures beginning in the summer of 1969 and 

 lasting to the spring of 1970 were not caused by 

 anomalous heat exchange. Thus, horizontal advection 

 and possibly, to a lesser extent, diffusion play a domi- 

 nant role in the temperature variability at OWS-V. 



It is interesting to note that the surface divergence as 

 reflected by changes in the depth of a, 26 has no annual 

 periodicity. The 6-yr record shows that large baroclinic 

 variability occurs at time scales of more than 55 days 

 with largest variability occurring at the interannual 

 scale. 



OWS-V is located in a dynamically active ocean area 

 with the area of highest net annual heat loss in the 

 North Pacific lying over 1,(X)0 km upstream. Relatively 

 large meridional temperature gradients vary seasonally 

 and probably also from month to month. Velocity varia- 

 tions of the Kuroshio Extension at the time scales con- 

 sidered here must also be expected. Consequently, di- 

 vergence and horizontal advection play an important 

 role in the variability of the observed properties, ob- 

 scuring the effects of local atmospheric forcing. 



The preliminary analyses reported here show that im- 

 portant properties of the ocean structure can be ob- 

 tained from a monitoring station such as OWS-V. It 

 may be more difficult, however, to relate changes in the 

 structure with local atmospheric forcing. In this case the 

 effects of heat exchange across the sea surface are ob- 



scured by other processes. Some of these processes could 

 possibly be determined by measurements that have not 

 been made on weather ships. Obviously, anomalous 

 atmospheric forcing must produce anomalous ocean 

 conditions. It appears that these relationships can be es- 

 tablished best if fields of properties in ocean and atmos- 

 phere are monitored in order that the effect of diver- 

 gence and advection can be determined, or that area 

 integrals can be obtained. 



ACKNOWLEDGMENTS 



We thank A. Bakun, Pacific Environmental Group, 

 NMFS; R. L. Elsberry, Naval Postgraduate School; and 

 S. Tabata, Institute of Ocean Sciences, Sidney, B.C., for 

 reviewing the manuscript and making many useful com- 

 ments. 



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