IV-19 



smoothing action of thermal conduction, and no further refinement of the tempera- 

 ture distribution can occur; in this way, a length- scale characterizing the smallest 

 temperature 'eddies' is determined." 



Some recordings of the microthermal variations at various depths are 

 shown in Figure IV-5. 



DEPTH: 25ft 



DEPTH: llOff 



40 YD 



FIGURE IV-5 



MICROTHERMAL VARIATIONS AT 

 VARIOUS DEPTHS (AFTER URICK 

 AND SEARFOSS) 



The scale and amplitude of the dominant fluctuations are seen to be substantially 

 greater at a depth of 110 ft than at a depth of 25 ft, as would be expected by the 

 above argument; in fact, a dominant patch diameter of the order of twice the 

 depth seems to be in general agreement with the recordings shown. Note that at 

 a depth of 170 ft the amplitude of the patches appears to have decreased somewhat, 

 indicating that the microthermal structure is again more uniform. The dominant 

 patch diameter has been plotted versus the depth for a fair number of such 

 recordings, and the resulting plot is shown in Figure IV- 6. The outer scale of the 

 patches is seen to agree quite well with two times the depth of the observation. 



artbur H.IlittlcJnt. 



S-7001-0307 



