CXD 



2 



'3 r« rr. ^ ..r 0,^05 / ^c^/Z-S/a^ 



(1I.49» 0-^ ^ ,1,59 X 10 v[0.50 + 0.125+ -; — — I e dc] 







^ 2 Ztt 



The contribution of the integral to equation (11.49^ is quite small and the 



2 

 value of or can be given by equation (11,60) where v is in meters per second, 



(11,50) a-J- ^- 0.99- 10"^ v 



2 

 Similarly c can be found to be equal to 



(11-51) ^j ■^- 0.60 , 10"^ V 



These values of the upwind and cros-swind slope contributions are in better 



agreeraent with the observations than those which result from equation (11.43) 



2 2 



although Cox and Munk found cr and cr to be nearly equal. Perhaps the dis- 

 crepancy can be explained by the nature of the site at which they obtained 

 their observations,* 



If tlie ratio,, jav/gj used in deriving equation (11.42) had been of the form 

 iJ-v /g where v is a constant equal to the wind observed at the time of the ob- 

 servation, then the integral over a would be a function of v such that the ex- 

 ponent would be {-a jZ - 8/(va) ). For a surface wind of 15 m/sec there 



2 



would be a. tendency toward a greater contribution to (r than observed by Cox 



2 



and Munk, and similarly a smaller contribution to cr„ . 



y 



Barber [1954] has studied the angular variation of waves with a period 

 near two seconds in Waitemata Harbour, Auckland. He found an angular vari- 

 ation somewhat like [cos 6] . However, his results cannot be compared with 

 these results as he writes that "the wind was about 15 knots and 2 sec waves 



* See also the end of this chapter, 



24.3 



