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difference between Zs and the measured water column abcve the sensor 

 at mean water represents the average tide level during the record. 



6. Development of Curvature Terms 



As the next step, the curvature terms are created by 

 subtracting the colinear slope terms and dividing by the distance 

 between the center of the slope measurements. 



7. Significance of the Signals in Linear Theory 



The absolute pressure transducer signal can then be 

 considered to be in the form: 



P(x,y,t) = Y -K cos (k X + k Y - ot) (psia) (A. 36) 

 2 p X . y-' 



and the differential signals in the form: 



P^(x,y,tl ^ - Y I k^ Kp sin (k^x + k^y - at) (psid) (A. 37) 



P.,(x,y,t) = - Y f k K sin (k x + k y - 0t) (psid) (4.38) 



y "^ y P X y I 



