and 17-27 kn were obtained by 

 averaging Hellerman's values for 

 Beaufort force 34 and 5-6 respec- 

 tively. ACi of 2.43 x 10" 3 was 

 used for all winds greater than or 

 equal to 28 kn. Use of these values 

 permits comparison with Hellerman's 

 work. It has the disadvantage of being 

 at variance with the recent conclu- 

 sions of SethuRaman and Raynor that 

 C j^ does not vary with mean wind 

 speed. However, it may be that at 

 wind speeds above the maximum 

 10 m sec " (20 kn) studies by 

 SethuRaman and Raynor, there is a 

 dependence of the roughness length, 

 a , and thus C ^ , on the mean 

 wind speed. This would explain the 

 findings of many investigators who 

 have formulated C ^ in terms of 

 mean wind speed. 



Data for the wind speed distri- 

 bution was taken from the Table 3A 

 of the U.S. Naval Weather Service 

 Command Series of Surface Synoptic 

 Meterological Observations for North 

 American Coastal Marine Areas 

 (SSMO) (U.S. Naval Weather Service, 

 1970), for each month at each coast- 

 al area. The table has the wind 

 distributed into eight directions with 

 five wind speed intervals; 0-6, 7-16, 

 17-27, 2840, and 41 + knots. The 

 table lists the percentage frequency 

 f y. , of the eight directions N, 



NE, E, SE, S, SW, W, NW at the wind 

 speed interval indicated. The mean 

 wind speed in the interval was estimat- 

 ed as the average of the range of 

 speeds for that interval, except for the 

 41 + interval, for which 41 knots was 

 used as the mean wind speed. 



WIND DATA 



PROGRAM TAUCOM 



The actual computation of the 

 contribution to the wind stress from 

 direction j was calculated as: 



r j = Z>fc4£-iW : a) 



where (C A ) - b is the drag coeffi- 

 cient appropriate to the speed inter- 

 val i, f ;,!. is the percent frequency of 

 the total wind distribution occurring 

 within speed interval i from direction 

 j, and Wi is the mean wind speed in 

 interval i. The total wind stresses 

 were then computed as: 



Computations for wind stress were 

 carried out in program TAUCOM, 

 (Appendix A). In the program, the 

 wind speed squared was designated as 

 follows. 



UA(3 knots)=23 777.6 

 cm* sec" 



UB(11.5 knots)=349399.2 

 cm 1 sec"*" 



UC(22 knots)=1278708.6 

 cm sec " 



UD(34 knots)=3054 105.8 

 cm 1 sec " x 



UE(41 + knots)=4441 134.8 

 cm *" sec * *" 



T fc = Z T\ 



v£ r »' 



and the drag coefficients were designa- 



(2) ted CA through CD with values from 

 0.85 x 10~ J through 2.43 x 10" 3 . 

 Each direction towards which the 



(3) wind was blowing was assigned a 



