changes in isotherm depth is correct in either sense, but after 4 

 hours of continuous recording, changes will have occurred at the 

 beginning of the section. The structures represent a spatial plot 

 rather than a time shift, since the advective and vertical oscilla- 

 tion movements caused by internal waves in strong thermoclines 

 occur more slowly than does the movement of the ship across the 

 section. The detailed thermal structure data to be presented can 

 be described as vertical sections in the sea in the same sense as 

 oceanographic sections derived from serial station data. 



The vertical scale is not entirely linear, since the thermistor 

 chain assumes a slight curvature between the vessel and the weight 

 at the end of the chain. For exact depths the linear depths on the 

 analog record of thermal structure can be multiplied by the factors 

 given in table 1. 



TABLE 1. DEPTH FACTORS FOR CONVERSION 

 OF LINEAR SCALE TO TRUE DEPTH 



Linear Recorded Scale 



Depth factor * 

 (for 100-foot intervals) 









100 



0.930 



200 



0.955 



300 



0.980 



400 



1.005 



500 



1. 030 



600 



1.055 



700 



1.080 



750 



1.105 



The thermocline normally occurs where the ratio of linear 

 depth to true depth is nearly unity. For practical purposes the 

 linear scale is accurate and is used throughout this report. 



*Smith, E. L. , Determination of Towed Configuration and Sensor 

 Depths of the USNEL Thermistor Chain , U.S. Navy Electronics 

 Laboratory Report, 1966 (in preparation). 



