centrations which have shown a maximum at 150 

 m in the subsurface waters show a general de- 

 crease in concentration to 500 m, then remain 

 fairly constant to the bottom (figs. 38-43). 



Arctic Bottom Water (900 m— Bottom) 



From the bottom of the Atlantic layer down to 

 2000 m there occurs a steady though slight de- 

 crease in temperature (0.00 to — 0.43°C) while 

 salinity (34.97 to 35.01°/oo) remains virtically the 

 same (figs. 32-35). Dissolved oxygen concentra- 

 tion is 6.4 to 6.8 ml/1. Saturation is everywhere 

 greater than 80%, indicating a well aerated basin 

 (figs. 36, 37, 102, and 103). Because of the 

 arbitrary restriction to remain inshore of the 2000 

 m bottom contour, no detailed study of this water 

 mass was attempted. 



Currents 



Direct current measurements were taken at five 

 stations during WEBSEC-71; observation levels, 

 water depth, length of observation and station 

 number are indicated in table 3. The records 

 revealed a layered system in which surface cur- 

 rents varied significantly in direction and mag- 

 nitude from the more coincident mid-level and 

 bottom currents. Figure 2 details the geographi- 

 cal location of the current meter arrays. 



The data from the hydroproducts current me- 

 ters were digitized and vector averaged over 15 

 minute intervals prior to final vector summing for 

 presentation in figures 104-108. Similar proce- 

 dures were used in analyzing data from the 

 geodyne system with initial averages extended 

 over a one hour period. 



While occupying all current meter stations dur- 

 ing WEBSEC-71, the motion of the vessel swing- 

 ing at anchor introduced significant variation into 

 the recorded velocities. Operating procedures 

 were such that the current meter arrays had to be 

 suspended from the vessel when at anchor. Mag- 

 nitude of these variations can be estimated at 

 station 23 by examining a log of the vessel's 

 headings which was recorded at 15 minute inter- 

 vals for a 20 hour period. These records showed 

 that the vessel moved through a maximum arc of 

 123° during the full period, and through an aver- 

 age arc of 9.8° in 15 minutes. Assuming uniform 

 motion during a 15 minute period, a swing of 9.8 



12 



Table 3.— Direct current measurements taken at five sta- 

 tions during WEBSEC-71, August-September 1971. 



HP#— Hydroproducts Current Meter Model 501, operated by 

 USCG 



GE#-Geodyne Current Meter Model 102, operated by USCG 



would produce a recorded velocity of 0.058 kts. at 

 right angles to the vessel's heading. The max- 

 imum swing during any 15 minute period was 58° 

 which introduced a velocity of 0.35 kts. Examina- 

 tion of the average current speed indicates that 

 the 0.058 kts. induced by the vessel motion is 

 often equal to or greater than the information 

 recorded on the current meter strip charts. Obvi- 

 ously, instantaneous or 15 minute averages are 

 rendered nearly useless by such motion. Only the 

 trends revealed by long-term vector averages 

 (figs. 104-108) can be considered significant 

 under these circumstances. 



Surface currents (2-3 m level) normally fell 

 within the same quadrant as the wind direction 

 unless the winds were of insufficient speed (<5 

 kts., such as at stations 23 and 69, fig. 27). In 

 general, the surface currents were too weak and 

 random to determine normal flow patterns and 

 their relationship to local geography, meteorology 

 and hydrological conditions. Sudden shifts in sur- 

 face current direction were observed at station 69 

 (speed, however, remained nearly constant at 



