erroneous data values. If more than 5 jumps or spikes in a row or a total of 

 100 bad data points for the file are found, the program stops interpolating 

 and any further editing. At this point, the program analyzes the data and 



prints a flag indicating there is a problem with the file. If the variance is 



2 

 less than 0.001 m , the record is not analyzed. After editing, the first five 



moments of the distribution of sea-surface elevations are again computed. A 

 cosine bell data window is applied to increase the resolution for the energy 

 spectrum of the file; use of the data window is discussed by Harris (1974). 

 After application of the data window, the program computes the variance spec- 

 trum (proportional to energy spectrum) using the FFT procedure. After the 

 data files are analyzed, the results are eliminated for files that were 

 flagged as bad or appear inconsistent with simultaneous observations from 

 nearby gage sites. Frequently, the spectrum and/or distribution function of 

 sea-surface elevations are examined to determine if the data are acceptable. 

 After the analysis results are edited, monthly summaries of wave heights and 

 periods are generated. 



44. Unless otherwise specified, "wave height" in this report refers to 



the energy-based parameter H (defined as four times the standard deviation 



o 

 of the sea-surface elevations) . 



45. The wave period T is defined as the period associated with the 



P 

 maximum energy in the spectrum. This is resolved by partitioning the spectrum 



into frequency bands of equal width and determining the band with the maximum 

 energy density. The period reported is the reciprocal of the center frequency 

 (e.g., T = 1/frequency) of the spectral band. Since the spectral bands are 

 of equal frequency width, namely 0.010742 Hz (e.g., 11/1,024 sec), the analy- 

 sis provides uniform resolution in frequency. However, the resolution in 

 period is not uniform since the period intervals become larger for lower fre- 

 quencies. Because of the convention of reporting the period at the center of 

 the interval in combination with the varying width of the period intervals, 

 only a discrete set of period values was possible (Table 1). The wave periods 

 used in this report have been rounded to the nearest second before summariza- 

 tion. Complete information about the energy contained in all frequency bands 

 can best be obtained by inspecting the full spectrum, examples of which are 

 included in Appendix B for gage 625 during storm wave conditions. 



24 



