Total energy spectrum: 



E, + E, 



1/2 (A^ + C^) 



(9) 



Rotary coefficient: 



R. = '^ ■ 'a 



(10) 



A 



In the above and following equations, the overbar represents an average 

 of a number of frequency contributions, that is, a band average over 

 values determined at discrete frequencies by a finite Fourier transform. 



Rotary cross-spectra were computed between selected current velocity 

 records. For the measured currents, the dominant direction of rotation is 

 clockwise. The coherence Yr between clockwise rotating components is 

 given by: 



^C 



1/2 



1 2 



(11) 



where the subscripts 1 and 2 indicate values from different current meters, 

 The phase difference Xq between clockwise rotating components is given by: 



tan X, 



C C sTn (0 - ) 



12 12 



(12) 



c c cos (0 -"'0~r 



12 12 



Cross-spectra between anticlockwise rotating components for different 

 current records and between anticlockwise and clockwise components for 

 different current records were determined using methods described by 

 Mooers (1973). 



Standard cross-spectra were also computed between selected east-west 

 and north-south velocity components. Of primary interest is the coherence 

 between these components. The coherence y is given by: 



