TM No. 327 



CONCLUSIONS 



Based on tiae data presented herein, the follovring conclusions are drawn 

 with respect to the five- questions posed at the beginning of this report. 



1. Although the water mctian in the Northeast Providence Channel is 

 of necessity related to the water a;.otion in the Tongue^ it is not apparent 

 what dynamic regime exists in the Tongue for a given dynamic regime in the 

 Northeast Providence Channel (or vice versa). The complex flow patterns 

 exhibited by the deep drogues at T2 support this. In other words, if the 

 current structure were well known in the Northeast Providence Channel area, it 

 would still be most difficult to predict the current structure in the Tongue. 



2. The only eddy motion observed was found along T2 at depths of 60O 

 and 1500 meters. The two eddies at 60O:. meters had radii of 3 and I3 kilometers;- 

 the eddy at I5OO meters had a radius of 13 kilometers. Although eddy motion 

 was not observed at the other transects, it may occur from time to time in 

 either the Northeast Providence Channel area or the Tongue of the Ocean. The 

 duration of the eddies would depend on the differential force coupling between 

 the two areas. 



3. Vertical current gradients generally decreased in magnitude from 

 the Northeast Providence Cliannel to the Tongue of the Ocean. The maximum 

 positive (increase with depth) and maximum negative (decrease with depth) 

 gradients were found at Tl, whereas the minimum positive and negative gradients 

 were found along T2. Vertical current gradients in the Tongue varied from 

 +0.7 to -2.1 cm/sec per 100 meters. Although vertical gradients ma^ be stronger 

 or weaker from time to time, especially in the upper 5OO meters, these are 

 probably representative values of the mean. 



k. Conclusions regai"ding tidal motion and the mixing of bank water 

 with Tongiie water in the sur-'face la;<"er will be discussed in a subsequent 

 report . 



5. Relatively little tidal data has been gathered in the Tongue, 

 precluding aziy accurate analysis of wind drift of the surface water in relation 

 to tidal data. 



In addition to the abce/a comments pertaining to the aforementioned 

 questions, the following conclusions have been reached. 



Current speeds generally decrease in magnitude from the Northeast 

 Providence Channel ta the Tongue of the Oceaxi. 



The net in-channel flow observed along ths first two transects is 

 probably not a steady state phenomenon , although outflow could have occurred 

 at depths at which no measurements were made. 



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