The current meter at 100m depth on the deep 

 mooring yielded 30 days of data before a partial 

 flooding of the instrument occurred, while the 

 lower meter malfunctioned and yielded no usable 

 data. The depth gauge on the deep mooring 

 flooded and no data were obtained. 



Initial analysis of the data reveals average 

 velocities in the Labrador Current that are 

 parallel to the bottom contours with magnitudes 

 of 46 cm/sec at 120m depth and 18 cm/sec at 

 385m depth. Spectral analysis indicates that the 

 major variations of the current occur at a time 

 scale of 12 to 16 days and that these variations 

 are coherent with the local wind field. 



Two BTTs (Buoy Transmitting Terminal) 

 were used in 1977, platform identifications 0647 

 and 0671. These were of the same type as those 

 used during IIP-76 (CG-188-31). 



Buoy 0647 was deployed on 13 April 1977 at 

 2100Zin position 47°02'N, 47°15'W. It was al- 

 lowed to drift until 1815Z 22 April when it was 

 recovered in position 45°27'N, 47°26'W (figure 

 15), a Handar Inc. automatic direction finder. 

 Model 602 A was used to locate the buoy and to 

 test the electronic package before deployment. 



This buoy provic" \ two important inputs to 

 CUP. The first was the speed of the Labrador 

 Current. This current was measured using 

 hydrographic survey techniques. This survey 



measured a maximum velocity of 44 cm/sec. The 

 buoy showed that the speeds were closer to 60 

 cm/sec, an important difference when drifting 

 icebergs. The second important input was ob- 

 tained from the direction of the buoy's drift. 

 The hydrographic survey showed a section of the 

 Labrador Current was changed from its normal 

 southerly direction and was flowing in a north- 

 easterly direction. It was not known for certain 

 that this was an accurate picture of the current. 

 "When the buoy entered this area it also swung 

 back towards the northeast and followed the di- 

 rection indicated by the survey very closely. This 

 information allowed CUP to have a much higher 

 confidence in their product. 



Buoy 0671 was deployed on 20 April 1977 at 

 2351Z, but stopped transmitting the next day. 

 Buoy 0647 was redeployed on 31 May 1977 at 

 1242Z but stopped transmitting on 2 June. At 

 the time of the apparent failure, both buoys were 

 indicating good battery voltages and for several 

 days the cause of the failure was unknown. How- 

 ever, when the EVERGREEN returned to St. 

 John's, Newfoundland, personnel from the fishing 

 vessel Cape Wrath II returned Buoy 0647. It 

 had become entangled in the ship's fishing nets. 

 The use of BTT buoys in areas where fishing is 

 extensive will have to be used with the under- 

 standing that the mortality rate will be higher 

 than in remote regions of the ocean. 



23 



