Daily visual surf observations on Oahu, Hawaii, USA of the Goddard-Caldwell collection starting 1968 (NCEI Accession 0001754)

The caretakers of the dataset typically cross-check observations among the various reporters for quality control. The daily value in the GC set represents the upper end of the reported height range, which is roughly equivalent to H1/10, for the observing time and location with the highest breakers along a given coast facing a similar direction. For the north shore, most observations are taken at Sunset Point, which is usually one of the areas of highest surf under the dominant northwest swells.

For days of extreme surf with heights greater than 15 Hs, visual observations are reported from Waimea Bay, where breakers are closer to shore. For the south shores, Ala Moana is usually the reporting site. Observations from the west and east side of Oahu have also been recorded although these reports are of lower quality.

Comparisons of the Goddard-Caldwell collection to 1981-2002 data from NOAA buoy 51001, which is located roughly 400 km west-northwest of Oahu, show the north shore surf observations are temporally consistent with the shoaling-only, buoy-estimated breaker heights and have an uncertainty of 10 to 15% of the surf height. Files are in ASCII text by year.