TO 64° 43' S 

 30*14' E 



FIGURE 39. Map of the Pacific Ocean showing the 

 distribution of the deep scattering layer along the tracks 

 of the USS HENDERSON and the USS NEREUS. Solid 

 lines indicate the continuous or almost continuous day- 

 time development of the layer. Dotted lines show the 

 intervals during which indications of the layer were rare 

 of entirely absent from the fathogram. 



\ X i. *VV««?«S-©« V C Q < > "« C Q it *± *- tf rf 



Outgoing Signal 



■» »»••■» a 



-- 1 1 ■ 1 I 



• ' - ■ *s>|Si 



Deep Scattering L 





Sunrise at 0545 



0600 



0700 



0800 



FIGURE 40. A. Fathogram showing the daytime development of the deep scattering layer at 200 to 225 fathoms on 8 December 1946 in 

 the vicinity of latitude 03° N and longitude 131° W. Note formation of the scotterers into a layer at about 0615 hours or shortly after 

 sunrise. Earlier downward descent of the scatterers is not apparent on this type of fathogram because of the long length of the outgoing 

 sound signal and general extension of this signal caused by near-surface scattering. 



• • • o o o e 



Deep' Scattering Laye 



84 



B. Fathogram showing daytime development of the deep scattering layer at 275 fathoms on 28 January 1947 in the antarctic in the 

 vicinity of latitude 62° S and longitude 117° W. This was one of the few instances in which the layer was well-developed in the antarctic. 



