U^ = l.lUjo for F < 10 miles (16 kilometers) 



U^ = RUio for F > 10 miles 



where U^ is the overwater windspeed in meters per second; R 

 is given in Figure 3 . If windspeed was measured overwater and 

 adjusted to a 10-meter height, U^ = Uiq- 



0.5 



Windspeeds are referenced 

 to 10-meter level 



10 15 20 26 30 35 40 kn 



5 10 15 20 25 30 35 40 45 50 55 60 m/S 



-I u 



5 10 IS 20 25 30 35 40 45 mph 



Figure 3. Ratio, R, of windspeed overwater, Uy, to windspeed 

 overland, Ul, as a function of windspeed overland, 

 Ul (after Resio and Vincent, 1976). 



(c) To correct for wind instabilities over fetch lengths 

 greater than 10 miles: 



Ua= 0.71 ul-23 



where U^ is the adjusted windspeed in meters per second. If 

 the F < 10 miles, U| = U^. 



(d) To correct for air-sea temperature differences, 



Ua = ^T ^A f°^ F > 10 miles 



U^ = Ua for F < 10 miles 



where U^. is the new windspeed adjusted for the temperature dif- 

 ference; R-j is given in Figure 4. 



