LAUSR

Characterizing the uncertainties in buoy ocean wave records is critical not only for understanding the limitations of in situ wave measurements but also for interpreting the implied accuracies of the remotely sensed products, in which these buoy data are used as validation references. This letter preliminarily assesses the error of long-period swell heights (Hss) representing specific directional wave partition energy observed from deep-water buoys moored in the Northeast Pacific (NEP). We propose a buoy Hss error estimation method by combining dual and triple collocation using data derived from buoys, two kinds of space-borne radars, and numerical simulations. Compared to traditional methods, the proposed approach can reveal “absolute” errors (with respect to the underlying truth) from buoy Hss, accepting and then confirming that Hss from buoy, satellite, and model are all uncertain. This study simultaneously employs ocean swell products derived from synthetic/real aperture radars (SAR/RAR) (Sentinel-1A/B and CFOSAT/SWIM) and WaveWatch IIIRegistered trademark. ocean wave model hindcasts to diagnose the accuracy of the Hss values observed by buoys of National Data Buoy Center (NDBC) and Coastal Data Information Program (CDIP) during the period from July 2019 to October 2021. We quantify that the NDBC’s 3-m heave-pitch-roll buoy (CDIP’s Waverider buoy) recorded Hss have root-mean-square error (RMSE) of 0.17 m (0.12 m) or have about 10.65% (7.06%) uncertainty relative to the mean Hss value (approximately 1.6 m). Our findings imply that the reference value uncertainties should be taken into account when understanding direct satellite Hss validation against buoy in situ.