T.M. No. 55 - November 1954 



North Atlantic Coast Wave Statistics Hindcast by Bretschneider- 

 Revised Sverdrup-i^unk l^ethod by Thornd i ke Savi Me, Jr. 



Detailed wave statistics for deep water, based on hindcasts from 

 synoptic weather charts for the 3-year period 1948-1950, are pre- 

 sented for four stations in the North Atlantic: off Penobscot Bay, 

 l^aine; off Nauset Beach, Cape Cod, [Massachusetts; off New York 

 Harbor entrance; and off Chesapeake Bay entrance. An example of 

 the method for obtaining shallow-water wave data at a point between 

 stations by interpolation and refraction analysis is calculated for 

 Long Branch, New Jersey. 



T.M. No. 56 - October 1954 



An Electronic Wave Spectrum Analyzer and Its Use in Engineering 

 Problems by Wi I lard J . Pierson, Jr. 



The theory of a wave spectrum analyzer designed and constructed 

 by S. S. Chang (see BEB T.M. No. 58) is described and the operation 

 of the filters in the analyzer explained theoretically. Methods for 

 computing information on the free surface wave spectrum, the energy 

 flux in the surf beats and in the waves, and the average "period" 

 are developed. These methods are simpi ified to make them practical, 

 and techniques for rapid evaluation of data are developed. A de- 

 tailed example is carried out. Several other possible applications 

 to engineering usage are shown. 



T.M. No. 57 - February 1955 



North Atlantic Coast Wave Statistics Hindcast by the Wave Spectrum 

 Method by G. Neumann and R. W. James 



Detailed wave statistics for deep water off the North Atlantic 

 Coast based on hindcasts from synoptic weather charts for the 

 3-year period 1947-1949, are derived by the relatively new wave 

 spectrum method as developed by Neumann, Pierson and James, for the 

 same offshore stations for which data was developed in T. M. No. 55. 

 The wave statistics are presented in comparable parameters to those 

 previously derived by the Sverdrup-Munk method and given in T. M. 

 No. 55. 



T.M. No. 58 - July J 955 



A Magnetic Tape Wave Recorder and Energy Spectrum Analyser for the 

 Analysis of Ocean Wave Records by Sheldon S. Chang 



An instrument which produces a wave record on magnetic tape and 

 from this tape produces a power (energy) density spectrum as a func- 

 tion of frequency is described. Photographs and detailed drawings 



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