11-59. Refer to figure 16-5 in your textbook. 

 How is sound in the illustration being 

 affected? 



1. It is reflected from the submarine to 

 the source 



2. It is reflected from the shadow zone 

 to the source 



3. It is refracted downward by the 

 slight velocity gradient 



4. It is refracted upward by the pro- 

 nounced velocity gradient 



11-60. Which of the following is most likely to 

 result when sound is reflected from a 

 solid object in the ocean? 



1. Scattered reflection 



2. Reflection with little loss in 

 intensity 



3. Absorption of reflected sound 



4. Reflection with loss in intensity 



11-62. Which of the following statements about 



the mixed layer depth (MLD) is INCORRECT? 



1. Of the three ocean layers, the MLD 

 is least stable and, as a result, 

 very little attention is devoted to 

 it 



2. Variations in the depth of the mixed 

 layer are influenced by day-to-day 

 heating and cooling 



3. Diurnal heating of the ocean's sur- 

 face will exert most influence down 

 to 30 feet below the surface 



4. Seasonal weather influences the 

 variation in the MLD of the world's 

 oceans 



In items 11-63 through 11-67, select from column 

 B the term or phrase applicable to each condition 

 in column A. 



11-61. 



Learning Objective: Recognize appli- 

 cations of sea surface temperature 

 (SST) observations and some seasonal 11-63. 

 effects of wind and temperature on the 

 mixed layer, and show the relationship 

 between these oceanographic parameters 

 and appropriate terms and phrases. 



Which of the following have applications 11-64. 

 for the information provided by sea sur- 

 face temperature (SST) observations? 



1. Antisubmarine warfare (ASW) opera- 

 tions only 11-65. 



2. Ocean fog forecasts only 



3. Search and rescue (SAR) operations 

 only 



4. ASW and SAR operations and ocean fog 

 forecasts 



A. Conditions 



The uppermost layers 

 of ocean water 

 increase to a density 

 greater than their 

 underlying waters and 

 sink to greater depths 



The wind blows the 

 surface water out of 

 an area 



In areas of vertical 

 boundaries between 

 cold and warm currents, 

 tongue-like protrusions 

 of warm water form 

 under cold water and 

 cold water tongues form 

 over warm water 



B. Terms/ 

 Phrases 



1. Instability 

 mixing 



2. Advection 



3. Convergence 



4. Divergence 



11-66. The winds cause surface 

 water to pile up in an 

 area 



11-67. Cyclonic wind moves sur- 

 face waters out of an 

 area permitting their 

 replacement by other 

 waters 



69 



