Introduction 



As a part of the problem of developing numerical wave 

 forecasting procedares for the North Atlantic Ocean, selected se- 

 quences of the weather maps for the North Atlantic for which wave 

 data were known to be available were studied in detail for the five 

 year period beginning in April 1955 and ending in March I960. 

 Certain dates and times of observations were selected for a variety 

 of reasons for study. For these dates and times, the National Insti- 

 tute of Oceanography provided copies of the wave records that were 

 obtained by the OWS Weather Explorer and by the OWS Weather Reporter. 



In total, about 800 wave records were provided, and a 

 complete spectral analysis is planned for about 400 of these records. 



This report is the first of a series of reports to present 

 in tabular and graphical form the results of these analyses. The total 

 nximber of spectra given is 114. 



Analysis procedures 



The original wave records varied in length, but almost all 

 of this first set were 15 minutes long. The crest to trough heights 

 of the highest waves in a particular record (uncorrected for cali- 

 bration effects) varied from a few feet to more than 60 feet in the 

 complete set of records. Bounds were set on each record just above 

 the highest wave crest and just below the lowest wave trough, and 

 the records were read to an accuracy of one part in a thousand 

 (nominally) over this range at an interval of 1.5 seconds throughout 

 the record. Thus a 15 minute record was reduced to a time series 



