Wave power variability and trends across the North Pacific. Issue 12 (2nd December 2013)

• Record Type: Journal Article
• Authors: Bromirski, Peter D.; Cayan, Daniel R.; Helly, John; Wittmann, Paul
• Is Part Of: Journal of geophysical research. Volume 118:Issue 12(2013:Dec.)
• Page Start: 6329
• Page End: 6348
• Publication Date: 2013-12-02
• Subjects: wave power -- wave model -- Pacific decadal oscillation -- extreme events -- climate regime shift -- interdecadal variability; Oceanography -- Periodicals; 551.4605
• DOI: 10.1002/2013JC009189
• Languages: English
• ISSNs: 2169-9275

Abstract

Abstract : [1] Multiyear climate variations influence North Pacific storm intensity and resultant variations in wave energy levels. The timing of these decadal fluctuations and strong El Niño's have had a strong influence on long‐term trends. Here we investigate variations in the North Pacific wave power, PW, 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 PW, 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 PW 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, PE, 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 PW across much of the North Pacific, in contrast to the long‐term increase of PW and Hs . This recent decrease is associated with the prevalent PDO cool phase that developed after the late 1990s. Variability and intensification of coastal PW and PE 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. Key Points: Wave power has generally increased across the North Pacific since 1950 Heightened wave power generally occurs during the warm phase of the PDO Extreme winter wave power events have upward trends along the U.S. Pacific coast