ESTUARINE MODEL OF SUB-ARCTIC PACIFIC OCEAN 453 



TuUy et al. (1959) studied this phenomenon and showed that 

 the temperature increase associated with the intrusion extended 

 from the surface to nearly 500 m depth. They depicted the extent 

 and advance of the intrusion by plotting temperature on the 

 isopycnal sheet cr, = 26.60 (Fig. 11).* In the eastern sub-Arctic 

 Pacific Ocean this sheet lies everywhere in the halocline. It is close 

 to the lower limit and below seasonal influence near the American 

 coast, and approaches the upper limit in the center of the Gulf of 

 Alaska. 



Comparison of Figs. 10 and 11 shows that the halocline and 

 isopycnal analyses coincide in every principal feature. In particular 

 the progressive Increase of the northward Intrusion of warm water 

 past the Canadian coast through 1957 and 1958 is equally apparent 

 in both analyses. It may be argued that the interpretation in 

 Fig. 10 is the more significant because It defines the features on 

 the interzone boundary, a surface of known consistent upward 

 transfer. 



Acknowledgmeni 



The considerable assistance of Dr. N. P. Fofonoff in the preparation 

 and criticism of the manuscript and of Mr. A. J. Dodlmead in the 

 preparation of the data Is gratefully acknowledged. 



REFERENCES 



Bennett, E. B. 1959. Some oceanographic features of the northeast 

 Pacific Ocean during August 1955. J. Fisheries Research Bd. Can., 

 16 (5), 566-633. 



Bloom, G. L. 1956. Current, temperature, tide and Ice growth measure- 

 ments. Eastern Bering Strait — Cape Prince of Wales, 1953-1955. 

 U.S. Navy Electronics Lab. Research Rept. 739, San Diego, Calif. 



Dodlmead, A. J. 1958a. Report on oceanographic Investigations In the 

 northeast Pacific Ocean during August 1956, February 1957, and 

 August 1957. Fisheries Research Bd. Can., MS Rept. Series {Ocean- 

 ographic and Limnological) No. 20. (Unpublished.) 



. 1958b. Oceanographic observations In the vicinity of the Aleutian 



Islands. Fisheries Research Bd. Can.; Pac. Ocea?iog. Group Bull. 

 5808. (Unpublished.) 



* The anomaly of specific gravity, at = (spec. gr. —1)1000, hence a-t = 26.60 

 corresponds to specific gravity 1.02660 (S\erdrup et al., 1942). 



