Thermal Structure Measurement 



The vertical thermal structure is 

 measured by means of bathythermographs, 

 isotherm followers, and thermistor bead 

 sensors. The thermistor beads are per- 

 manently affixed to the tower, floated 

 down from buoys, or suspended at 2-foot 

 intervals in a vertical string from a taut- 

 wire buoy system. 



Long-period thermal structure 

 data are obtained from thermistor beads 

 mounted at 6-foot intervals down one 

 tower leg. These are thermally lagged 

 so that the response time (r) is equal to 

 20 minutes. Temperatures are printed 

 on a digitized recorder, which is pro- 

 grammed for sequential interrogation of 

 each sensor every 10 minutes. For 

 special heat flow and insulation studies, 

 four similarly lagged beads extend into 

 the sea floor. 



The closely spaced, more rapid 

 response beads ( t = 20 seconds) in a 

 taut-wire buoy arrangement record the 

 most detailed thermal structure. Here 

 the temperature is referenced to the 

 bottom rather than to the surface. This 

 method shows the structure near the sea 

 floor in more detail, since sampling is 

 less influenced by surface action. The 

 data are recorded in analog form as well 

 as on punched tape. Prediction of thermal 

 structure is one of the objectives of these 

 studies. 



60° 70 c 



TEMPERATURE (°F) 



The temperature structure of the 

 water at the tower in summer 

 contains a strong thermocline, 

 while in winter the water is 

 nearly isothermal. The near- 

 bottom water is colder in summer 

 than in winter because of up- 

 wel I ing. 



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