for the Worth Atlantic Ocean. The original objectives of the subcontract 

 were to: 



1. Compare the results obtained using the Neuman spectrum with 

 those using the Bret Schneider and Darbyshire spectra. 



2. Optimize the grid size and time- step length. 



3 . Consider the effects of sea-air temperature differences and 

 other stability and atmospheric turbulence criteria on the effectiveness 

 of the wind in generating waves. 



h. Build in an automatic correction capability so that any available 

 wave observations will continually correct hindcasts used as initial 

 conditions in the forecast. 



After the project had started severaJ. problems previously unfore- 

 seen became evident so that a modification of the objectives was 

 necessary. Prij)rity was then given to improving the spectriom model, 

 preparing a new wave growth function, and adding the effects of dis- 

 sipation to the program. 



The point of departure for starting the subcontract was the previous 

 research on machine computations of wave spectra over the North Atlantic 

 Ocean performed by Baer^ ^ for a doctoral degree at New York University. 

 The data used for preparing a new growth function were the spectra com- 

 puted at New York University from the British shipborne wave records. 

 Various changes in machine programming to produce a better fit of 

 spectral shapes did not require additional data. 



A complete spectral analysis was made for a selected h60 out of the 

 approximately 800 shipborne wave records and the results were published 

 in both tabular and graphical form. The raw spectra of all h60 records 

 have been placed on magnetic tape and are available for any further 

 research. The foizr main locations in the North Atlantic where the data 

 were taken are as follows: 



Position A (62% 33°W) 

 Position I (59% 19°w) 

 Position J (52.5% 20°W) 

 Position K {^3°^, l6°W) 



These are the on- station positions for the weather ships in the eastern 

 North Atlantic Ocean. Except for a few records, each was of 15 minutes 

 duration and was reduced to a time series of 600 points. This series 

 was analyzed by an electronic computer so that the energy spectrum was 

 estimated at 60 points over the frequency range from zero to 0.333 

 cycles per second using procedures given by Blackman and TukeyV^;, 

 Final corrections and smoothing were then made on these estimates to 

 give the corrected spectr-um in units of (ft)^. These values were tabu- 

 lated for each wave record and the corrected spectrum plotted as a 



la 



