GRADIENT-STRENGTH MAGNITUDES 



The vertical-temperature-gradient field for Sample Area 8 

 (fig. 5) displays a gradient-strength range of three orders of 

 magnitude in degrees Celsius per foot. The gradient strength for 

 the field, in general, is 10" 2 °C/ft. In Area A' the vertical gradi- 

 ent increases one order of magnitude to 10 ~ l0 C/ft. Area A' 

 corresponds to the previously mentioned Area A of figure 4. It 

 was described as an area of converging isotherms and, hence, 

 of relatively- high-intensity vertical-temperature gradient. At 

 depths greater than 410 feet, the vertical gradient decreases one 

 order of magnitude to 10 " 3 °C/ft. 



The horizontal-temperature-gradient field for Sample Area 

 8 (fig. 6) also displays a gradient- strength range of several 

 orders of magnitude. The contoured gradient strength for the 

 field, in general, islO" 4 °C/ft, and gradient- sign changes occur 

 at zero contours. In area A" the horizontal gradient increases 

 one order of magnitude to 10 " 3 °C/ft. Area A" corresponds to 

 Areas A and A' of figures 4 and 5, respectively. Below 420 feet 

 the horizontal gradient decreases one order of magnitude to 

 10" 5o C/ft. The horizontal-temperature gradient is zero in the 

 region of gradient-sign changes. The horizontal-gradient 

 strengths referred to are the maximum obtained at a specific 

 depth. 



Comparing the vertical and horizontal gradients shows that 

 they differ in strength by two orders of magnitude . When the 

 vertical and horizontal gradients change orders of magnitude , 

 they appear to do so simultaneously. 



On the basis of results obtained with the Russian thermistor 

 chain, Lyamin (1965) wrote: "When the temperature fluctuations 

 are compared with the magnitudes of the vertical temperature 

 gradient, they are seen to be proportional to each other. This 

 relationship is noted in all cases without exception and indicates 

 that the temperature fluctuations recorded by horizontally dis- 

 placed transducers are the result of the vertical displacement of 

 the water layers. " 



The interrelationship of the magnitudes of horizontal- and 

 vertical-temperature-gradient strengths holds throughout all 17 

 sample areas with but a single exception. In Sample Area 9 it was 

 found that, in regions of very sharp thermocline (high vertical- 

 gradient values) where the vertical variations in the temperature 



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