New ways to measure waves and their effects at NOAA tide gauges: A Hawaiian‐network perspective

We use the standard deviation (sigma) of continuous 1 s water level sampling at 46 U.S. NOAA tide gauges available since 1996 as a high-frequency variance measure. Sigma estimates local infragravity and incident wave band variability, is significantly correlated (r = 0.5–0.9) to significant wave height (Hs), and scales linearly to local observations and output from the global ocean wave reanalysis at most ocean-exposed and harbor-sheltered locations. Empirical orthogonal functions of daily mean sigma from six Hawaii tide gauges distinguish northerly and southerly modes that closely match local Hs observations. Depending on tide gauge location, the 99% of daily maxima sigma can be as large as or larger than the nontidal residual component of the water level sample. Our findings provide new uses of land-based tide gauge data to estimate significant wave heights and dynamic water levels to better monitor for local conditions leading to impacts.