INTRODUCTION 



In 1922, Lewis F. Richardson, an Englishman, published his book 

 entitled Weather Prediction by Numerical Process . His manual procedures 

 for numerical weather predicting were impractical, however, because of the 

 length of time required to produce the desired results. Some twenty years 

 later, the advent of high speed electronic data processors made numerical 

 methods much more practical . After many trials and tribulations, somewhat 

 reliable numerical weather predictions on a limited basis and for the upper 

 atmosphere became available by the mid-1950's. During the past decade 

 rapid advances have been made, both in numerical theory and in the 

 sophistication of electronic data processing equipment. Presently, numerical 

 weather predictions are routine over vast areas of the globe with constant 

 improvements being made as researchers attack the various problems. 



Following a somewhat analogous pattern, the problem of ocean 

 wave prediction has also been attacked with considerable success during 

 the past two decades. Ocean wave predictions received serious con" 

 sideration beginning in the early 1940's after certain relationships among 

 wind speeds, wind directions, and fetch lengths on water surfaces had 

 been empirically determined. During the 1950's prognostic wave charts, 

 giving wave heights and directions over the oceans, were being produced 

 manually at certain weather centers for ship routing and operations. It 

 was soon realized, however, that the subjectivity and tediousness of these 

 manual forecasts required a more practical method for obtaining them. 



By the early 1960's raw weather data from land and ship obser- 

 vations were being fed into electronic computers to produce synoptic 

 and prognostic charts of surface pressure . From these the winds over the 

 oceans were computed and used as computer inputs to produce synoptic 

 and prognostic charts of wave heights and directions,, At first, these 

 forecasts were limited in their application because they yielded only 

 the wave heights and directions instead of the more sophisticated and 

 realistic ocean wave directional spectra. The necessity for the spectral 

 approach to wave forecasting soon became evident . 



The Naval Oceanographic Office was given the task of preparing 

 a wave spectra climatology for the North Atlantic Ocean in 1961 . It 

 was immediately recognized that the immensity of this task required the 

 use of electronic computers and numerical procedures. Accordingly, con- 

 tracts were let with private research groups qualified and experienced in 



