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National Advisory Committee for Aeronautics, Technical Notes - A Statistical Study of Wave Conditions at Four Open Sea Localities in the North Pacific Ocean

The present study of wave conditions in the Pacific Ocean was under—
taken by the Scripps institutign of oceanography to investigate the
following characteristics of the sea and wind which are considered. to be
of primary importance in the structural design of flying boats and sea-
planes: (a) Wave height and frequency of occurrence, (b) wave length-
height ratio and frequency of occurrence, (c) wave velocity and its
relation to wave lengths, (6.) wind velocity, and (.e) wave shape-

For each of four open-sea localities representing conditions for
the main regions of the Pacific Ocean, the percentage frequencies of
wave heights and wave length-height ratios have been calculated by use
of weather maps and methods developed for forecasting sea and swell.
These data have been presented in graphical and tabular forms. Also
included in the present paper is the following information: Discussions
of the relation between wave velocity and wave length, tabulation of
wind-velocity distributions, discussions of wave shape, and examples of
the use of the figures. Comparison between computed and observed heights
was found to be satisfactory.

For a study of open-sea conditions, comprehensive observations are
lacking, and the few observations available are confined to wave height
onJy- Consequently, it was necessary to conmute wave heights and lengths
from weather maps by using the methods previously developed for forecasting
sea and swell. Daily comutations were carried out for each of four
representative localities of the Pacific Ocean for the 3-year period
1936 ~38. These computations form the basis for the summaries of wave
conditions which appear in the present report.

For each of the stations the percentage frequencies of wave heights
and wave length-height ratios have been calculated, and the data have
been presented in graphical and tabular forms. By frequency of occur-
rence in the case of wave heights is' meant the percentage of total time
the wave height lies within a specified interval. A practical lower
limit for specified intervals of wave height is 1 to 2 feet. By frequency
of occurrence in the case of length-height ratio is meant the percentage
of total time the length-height ratio lies within a specified interval.
The lower limit of length-height ratio is of primary importance. The
wind-velocity distributions have also been tabulated. Discussion of the
relation between wave velocity and. length and a discussion of wave shape
are included in the report.