Refer to figure 16-8 in your textbook. In items 

 12-10 through 12-16, select from column B the 

 type of deepwater transmission most closely 

 associated with each statement in column A. 



A. Statements 



12-10. The transmission 



path takes a conic 

 form with some 

 rays bent up and 

 others bent down 

 by refraction 



12-11. The velocity at a 

 depth above the 

 bottom surface 

 must be equal to 

 or greater than 

 the velocity at 

 the surface 



12-12. The temperature at 

 the surface is 

 constant within 

 0.4° F per 100 

 feet, and velocity 

 increases with depth 



12-13. The path prediction 

 is NOT generally a 

 function of velocity 

 gradients 



12-14. The transmission is 

 free from surface 

 thermal effects, and 

 most of the sound path 

 is in stable water 



12-15. Refracted-reflected- 

 refracted rays are 

 usually found in this 

 type of transmission 



12-16. The path consists of 



upward refractions and 

 downward reflections 

 and allows ranges out 

 to several hundred 

 miles 



B. Transmissions 



1. Surface dirt 



2. Deep sound 

 channel 



3. Convergence 

 zone 



4. Bottom bounce 



Learning Objective: Identify the 

 cause of ocean currents and the 

 effect of the earth's rotation on 

 their direction of flow, and recog- 

 nize the construction features of 

 the major current systems, their 

 parameters, where they flow, and 

 how and where they influence the 

 earth's climate. 



12-17. What is the principle cause of the ocean 

 currents? 



1. The prevailing winds 



2. The rotation of the earth 



3. The gravitational pull of the sun and 

 moon 



4. The unequal temperatures of the high 

 and low latitudes 



12-18. Due to the rotation of the earth, the 



pattern of deflection of the ocean sur- 

 face waters is toward the 



1. left in the Eastern Hemisphere 



2. right in the Western Hemisphere 



3. left in the Northern Hemisphere and 

 toward the right in the Southern 

 Hemisphere 



4. right in the Northern Hemisphere and 

 toward the left in the Southern 

 Hemisphere 



12-19. Which of the following statements relat- 

 ing to the direction of flow of the ocean 

 currents along the coasts of continents 

 in the middle and low latitudes of the 

 Northern Hemisphere is correct? 



1. Cold currents flow equatorward along 

 both the east and west coasts 



2. Warm currents flow poleward along 

 both the east and west coasts 



3. Cold currents flow poleward along 

 the east coasts, and warm currents 

 flow equatorward along the west 

 coasts 



4. Warm currents flow poleward along 

 the east coasts, and cold currents 

 flow equatorward along the west 

 coasts 



12-20. Two oceanographic features that have a 

 great influence on the climate of the 

 west coast of northwestern Africa are 



1. upwelling and cold currents 



2. low salinity and cold currents 



3. high salinity and warm currents 



4. rapid surface evaporation and warm 

 currents 



£ Refer to figure 16-9 in your textbook in 

 answering 16-49 through 16-55. 



12-21. The northern branch of the North Equa- 

 torial Current in the Caribbean that 

 flows to the north of Cuba is called the 



1. Florida Current 



2. Antilles Current 



3. South Atlantic Current 



4. Gulf Stream System 



71 



