654 EIGHTH PACIFIC SCIENCE CONGRESS 



ILLUSTRATIONS 



Fig. 1, — Idealized examples of simple salinity and temperatui'e structures 

 showing the characteristics of the natural-plots and log-plots. 



Fig. 2. — Types of simple temperature and salinity structure. There is an 

 upper and lower zone separated by a boundary zone. Either the 

 upper or lower zone may be absent or they may be congruous. 



Fig. 3. — Types of complex structure whei'e the successive gradients of pro- 

 perties in the boundary zone continue to increase or decrease from 

 segment to segment. 



Fig. 4. — Method of analysis of the logarithmic gradient in the boundary zone. 

 The conventional interpretation is indicated by the solid lines. Other 

 possible interpretations are mdicated by the dashed lines. 



Fig. 5.— Bathythermograph, Latitude 50' 24'N, Longitude 131° 34'W, 0304, 

 7 August, 1951. This illustrates step structure whose mean gradient 

 approximates a logarithmic gradient within small limits of error. 

 The circled points represent the standard depths that would have 

 been observed in a serial observation. 



Fig. 6. — Log-plot from a series of half-hourly BT observations in Juan de 

 Fuca Strait, Latitude 48° 13.8'N, Longitude 124° 09"W, 4 July, 1952. 

 These demonstrate that the hourly variation in the fine structure, 

 and in the depth and magnitude of the boundary zone, are greater 

 than the deviation from the best straight line through the points. 



Fig. 7. — Log-plots of the sei*ial observations at Latitude 54°21' N, Longitude 

 140 °05' W, on 0730, 10 August, 1950. These show that the structure 

 with respect to each independent property is unique. 



Fig. 8. — Application of the concept of index salinity in logarithmic structure 

 to the illustration of oceanographic data. 



Fig. 9. — Idealized temperature structures illustrating the formation and de- 

 generation of step structure due to diurnal heating and cooling in 

 the upper zone. 



Fig. 10. — Idealized sequence of structures illustrating the annual temperature 

 cycle in the upper zone in the northeast Pacific Ocean. (Reference 

 . . . Doe) 



