CONTENTS 



Page 



I INTRODUCTION 9 



II THE SPECTRAL COMPUTATION 10 



III ESSENTIAL EQUIVALENCE OF THE FFT AND COVARIANCE METHODS. . 11 



IV FFT AVERAGING NEEDED TO GIVE SPECTRA EQUIVALENT TO 



THOSE FROM THE COVARIANCE METHOD 15 



V SUMMARY OF COMPUTATIONAL FORMULAS USED FOR THE 



HURRICANE CARLA WAVE SPECTRA 16 



VI DISCUSSION OF HURRICANE CARLA WAVE SPECTRA 18 



VII STATISTICAL VARIABILITY OF THE SPECTRAL LINES 18 



VIII THE EMPIRICAL PROBABILITY LAW FOR THE SYMMETRICALLY 



NORMED RESIDUAL 50 



IX EMPIRICAL PROBABILITY INTERVALS FOR p(fm) 



BY SIMULATION 50 



X COMPARISON WITH CHI-SQUARED PROBABILITY INTERVALS 



FOR p[fm) 64 



XI COMPARISON OF THE EMPIRICAL DISTRIBUTION FUNCTION 

 OF THE SYMMETRICALLY NORMED RESIDUALS WITH THE 



CHI-SQUARED VERSION 75 



XII THE OUTLIER SPECTRAL LINES 78 



XIII WHY DOES CHI-SQUARED WORK FOR HURRICANE WAVES? 81 



XIV IMPLICATIONS FOR DIRECTIONAL SPECTRUM RELIABILITY .... 82 



XV SUT'IMARY AND CONCLUSIONS 82 



LITERATURE CITED 86 



APPENDIX 



A EFFECTIVE WIDTH 87 



B EFFECT OF A DETERMINISTIC LINE ON THE SPECTRUM 88 



C ASYMPTOTIC CHI-SQUARED PROPERTIES OF THE FFT SPECTRAL 



LINES FOR NON-GAUSSIAN, M-DEPENDENT WAVE TRAINS 93 



