Wave power variability and trends across the North Pacific

TitleWave power variability and trends across the North Pacific
Publication TypeJournal Article
Year of Publication2013
AuthorsBromirski PD, Cayan DR, Helly J., Wittmann P.
JournalJournal of Geophysical Research-Oceans
Date Published2013/12
Type of ArticleArticle
ISBN Number2169-9275
Accession NumberWOS:000329926200002
Keywordscalifornia coast; climate; climate regime shift; el-nino; Extreme events; heights; hemisphere winter; interdecadal variability; oscillation; Pacific decadal oscillation; projections; reanalysis; storminess; teleconnections; wave model; wave power

Multiyear climate variations influence North Pacific storm intensity and resultant variations in wave energy levels. The timing of these decadal fluctuations and strong El Ninos have had a strong influence on long-term trends. Here we investigate variations in the North Pacific wave power, P-W, determined from WAVEWATCH III (WW3) wave model significant wave height, Hs, and peak period data forced by NRA-1 winds spanning the 1948-2008 epoch. Over the entire hindcast, upward trends in Hs and P-W, especially in winter, are observed over much of the North Pacific, strongly influenced by an apparent storm intensification after the mid-1970s regime shift. Heightened P-W is concentrated in particular regions of the basin, and is associated with increased wave activity during the warm phase of the Pacific Decadal Oscillation (PDO). Wave power events, P-E, defined as episodes when Hs exceeded the 90th percentile threshold for at least 12 h, exhibit significant upward trends along much of the U.S. Pacific coast during winter months. Importantly, the hindcast exhibits a recent decrease in P-W across much of the North Pacific, in contrast to the long-term increase of P-W and Hs. This recent decrease is associated with the prevalent PDO cool phase that developed after the late 1990s. Variability and intensification of coastal P-W and P-E have important practical implications for shoreline and beach erosion, coastal wetlands inundation, storm-surge flooding, and coastal planning. These considerations will become increasingly important as sea level rises.

Short TitleJ Geophys Res-Oceans
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