TM No, 327 



INTRODUCTION 



Since accurate tracking of test vehicles in the AUTEC (Atlantic Undersea 

 Test and Evaluation Center) deep vater range depends in part on correlating 

 the effects of the dynamic oceanographic environment with data obtained by 

 the underwater instrumentation^ additional information on these environmental 

 factors is required. In addition, the results of past current measurements 

 have jbeen relatively unfruitful, largely because, of Inadequate planning and 

 lack of concentrated coverage . 



To learn more about the currents in the AUTEC area^ the Naval Underwater 

 Ordnance Station^ in cooperation with the Woods Hole Oceanographic Institu- 

 tion^ set and tracked parachute drogues in the Northeast Providence Channel 

 and selected areas of the Tongue of the Ocean^ Bahamas. These measurements 

 were made during the period ik February to 6 March I963. 



A preliminary report (TM No. 306 dated September I963) described the 

 purpose of the program^ the design of the drogue system^ and the navigational 

 equipment used in tracking the drogues. An analysis has been made of the 

 raw data presented in TM No. 306. This final report provides at least a 

 partial answer to the following questions: 



1. Can the motion of the water in the Northeast Providence Channel 

 be traced to the motion of the water in the Tongue of the Ocean (or vice 

 versa)? 



2. What is the mixing length (radius) of the predominant eddies in 

 the Tongue of the Ocean? 



3o What is the general magnitude of horizontal and vertical current 

 gradients? 



U, To what extent (and on what time scale) do turbulent shears 

 (normal to the bank walls) cause mixing and transport of bank water into the 

 AUTEC region? 



5. How is the wind drift pattern related to tidal data? 



RESEARCH VESSELS 



Two vessels were used during the program. The OCEAN PEARL^ a privately 

 owned, ketch capable of speeds up to 9 knots under power ^ was used by the 

 Woods Hole Oceanographic Institution under the direction of Mr. John Bruce, 

 WHOI, The HoJ,W, FAY, a research vessel capable of speeds up to 18 knots, 

 was used by the Naval Underwater Ordnance Station (on contract from Marine 

 Acoustical Services, Inc., Miami, Florida) under the direction of 

 Mr, G. S. Cook, NUOS. 



