Statistical analysis of visual wave observations and gage/radar measurements

This report presents results of a study conducted to determine the variability of observations made simultaneously by several different observers, to compare those observations with instrument measurements when available, and to look at the temporal variation of observed littoral conditions over a 25-hour period. Littoral Environment Observations (LEO) taken by individual observers were compared with the means of the observations obtained by all observers and with instrument-recorded data when available for a particular variable. Statistical analyses were performed for the different LEO variables to determine the following: (1) confidence intervals; (2) correlation coefficients; (3) standard deviations; (4) consistency between observer and gage; (5) effect of tides on estimation of parameters (i.e., did the estimates depend on the distance between observer and waves?); and (6) the statistical wave height to which LEO wave heights should be compared. The field experiment was conducted at Duck, North Carolina, at the Field Research Facility (FRF) of the Coastal Engineering Research Center on 15-16 August 1978. Six observers simultaneously recorded hourly LEO observations. Concurrent wave measurements were made from the FRF pier with gages and radar.