where 



H^ = deepwater significant wave height in feet 



Tg = the corresponding significant wave period in seconds 



R = radius of maximum wind in nautical miles 



Ap = p - p , where p„ is the normal pressure of 29.92 inches 



of mercury, and p is the central pressure of the hurricane 



V„ = The forward speed of the hurricane in knots 



U^ = The maximum sustained wind speed in knots, calculated for 

 30 feet above the mean sea surface at radius R where 



U^ = 0.865 U^^^ (For stationary hurricane) (3-33) 



U^ = 0.865 U^^ + 0.5 V^ (For moving hurricane) (3-34) 



^rmx ~ Maximum gradient wind speed in knots 30 feet above the 

 water surface 



^max = 0.868 [73 (p„ - p^) 1/2 . R(0.575f)] (3-35) 



f = Coriolis parameter = 2to sin(j), where w = angular velocity of 

 earth = 2ti/24 radians per hour 



Latitude (()>) 25° 30° 35° 40° 

 f (rad/hr) 0.221 0.262 0.300 0.337 



a = a coefficient depending on the forward speed of the 

 hurricane and the increase in effective fetch length, 

 because the hurricane is moving. It is suggested that 

 for slowly moving hurricane a = 1.0. 



Once Hq is determined for the point of maximum wind from Equation 

 3-31 it is possible to obtain the approximate deepwater significant wave 

 height H^ for other areas of the hurricane by use of Figure 3-34. 



The corresponding approximate wave period may be obtained from 



T =2.13 y/H^ (in seconds) , (3-36) 



where H^ is in feet (derived from empirical data showing that the wave 

 steepness H/T^ will be about 0.22). 



3-58 



