frequencies, due possibly in some part to shear waves, which have a 
stronger velocity signal than pressure signal. 
f. Also shown in the upper right corner of Figure E30 are numbers 
representing a possible modified pressure gauge gain (which should be 
1.0 for all cases in these runs). 
Data quality plots were used to identify cases with data that were clearly 
bad. Surface-corrected velocity spectra should cluster together, with one 
grouping each for alongshore and cross-shore velocities. Barring other sources 
of noise, these spectra should follow a chi-square error distribution. For the 
nominal 160 degrees of freedom with which these spectra were computed, the 
95-percent confidence interval extends from about 21-percent below to about 2- 
percent above the true value of each spectrum, or a range of about 4-percent. 
Though the true values are not known, members of a group of spectra were 
considered satisfactory if the range of spectral densities agrees to within about 
44 percent at each of the discrete frequencies in the nominal wind wave pass 
band of 0.04 to 0.32 Hz. Pressure data were considered satisfactory if Z(f) 
was reasonably uniform through the wind-wave pass band of frequencies, 
indicating consistent frequency dependence of velocity and pressure data. 
Excepting high-energy, low-frequency conditions, where shear waves may be 
influential, the nominal acceptable range of PUV-test results is 0.8 < Z(f) < 
1.2. Data acceptance criteria given here served as rough guidelines. Minor 
exceptions were tolerated in this analysis in an effort to maximize the amount 
of data considered to be useable. 
The mean current data contained either severe, persistent nonuniformity or 
some yet-to-be understood bias. It remains unclear what the source of the 
problem was or how to circumvent it. Consequently, any effects from mean 
currents were ignored, though the wind-wave parts of the current meter records 
seemed acceptable. Data that passed the quality control constraints were used. 
Final data sets 
Processed data satisfied three constraints: (a) start times and durations had 
to match FRF collections,(b) there were no exposed gauges, and (c) pass band 
frequency spectra satisfactorily met the constraints of the data quality plots. 
Table E4 lists the cases from the trough and crest subarrays that satisfied these 
constraints. More exposed gauges occurred in the trough subarray, and the 
current meter at station 30 was lost sometime on 15 October. Therefore, the 
total set of cases for the trough subarray is small. 
Appendix E Stationary Instrument Data E41 
