DATA ANALYSIS 



Magnetic Corrections 



Plantagenet Bank is well known as an area characterized by a pro- 

 nounced magnetic anomaly. Airborne geomagnetic measurements made by 

 the Hydrographic Office in January I96I provide an accurate description 

 of this magnetic distua-bance. These measurements have been utilized to 

 determine corrections for compass variation which have been applied to 

 the magnetic current directions at each of the following stations: 



Station Correction (degrees) 



A -13.5 



B - 9.5 



G -13.5 



Current Buoy -12.5 



Central Vector Diagrams 



At each anchor station a series of current measurements varying 

 in number from 19 to 25 was obtained at all observational depths. Cen- 

 tral vector plots provide a vivid means of representing time changes 

 of cxirrent speed and direction of such serial observations. These plots 

 have been constructed for each depth, as well as for the surface winds 

 (Appendix C). 



Vectors are numbered in chronological order. Wind vectors are 

 drawn in the direction toward which the wind was blowing. 



Progressive Vector Diagrams 



The progressive vector diagrams presented in Appendix D provide 

 another means of depicting the series of current data available at a 

 given depth. Such diagrams, constructed through successive graphic 

 addition of observed hourly velocities, provide indications of net 

 transport over the Bank. 



A limitation of this technique results from the somewhat unequal 

 time intervals between the consecutive observations at given depths. 

 In order to compensate for this deficiency, interpolated hourly veloc- 

 ities have been introduced into several data gaps, thus providing a 

 relatively undistorted displacement track. This technique is not in- 

 tended to be absolutely representative of the actual water particle 

 displacement but is intended to serve as an aid in the comparison of 

 gross current characteristics from depth to depth and from station to 

 station. 



Appendix D also includes progressive vector diagrams of the 

 current data obtained with the buoyed current meter plotted beside the 

 simultaneous anchor station observations at a corresponding l6-meter 



