Recent increase in summertime extreme wave heights in the western North Pacific

Abstract

Recent increase in summertime extreme wave heights (H10, June–August average of the highest 10% of significant wave heights at each month) in the western North Pacific is found by applying an empirical orthogonal function analysis to H10 derived from 3rd–generation wave model forced by 6‐hourly sea surface wind fields of NCEP‐NCAR reanalysis over the period 1980–2004. The leading principal component of H10 demonstrates that the highest four years of H10 during 1980–2004 occurred in the last 10 years. It is found that the recent increase in H10 corresponds to the recent increase in total duration of intense tropical cyclones (ITC, with central pressure below 980 hPa) in the western North Pacific. Time series of the total duration of ITC reveals that the highest three years of the total duration of ITC during the last three decades occurred in the last 10 years.

Long-term time-dependent stochastic modelling of extreme waves

“…More recent studies observe the continuation of this increasing trend into the twenty-first century (Caires et al 2006a;Dodet et al 2010), although there are still uncertainties as to whether, or to what extent, the trend can be ascribed to global warming (Wolf and Woolf 2006;Wang et al 2009). Increasing trends have also been found in other oceans than the Atlantic (Sasaki et al 2005;Gower 2002;Ruggiero et al 2010).…”

Future Projections of Extreme Ocean Wave Climates and the Relation to Tropical Cyclones: Ensemble Experiments of MRI-AGCM3.2H*

“…Emanuel (2005) showed that, since the mid-1970s, tropical cyclones have become increasingly destructive because of longer storm duration and greater intensity. Sasaki et al (2005) and Yong et al (2008) indicated that summertime extreme wave heights have increased in the western North Pacific during recent years resulting from intense tropical cyclones. Furthermore, extreme hurricane-generated waves in the western North Atlantic have also increased (Komar and Allan 2008;Bromirski and Kossin 2008), and Moore et al (2013) concluded that coastline changes to the U.S. East Coast were attributed to changes in hurricane-generated waves.…”

Responses of summertime extreme wave heights to local climate variations in the East China Sea

“…Their study estimated that the source of enhancement is about 2400 km south of Japan, coinciding with the geographical position of the cyclonic wind anomaly detected in our present study. Later, Sasaki et al [2005b] and Sasaki and Hibiya [2007] determined that the increase of summertime extreme wave heights was closely related to the increased duration of intense tropical cyclones. Moreover, Stowasser et al [2007] found that the average intensity (measured by the peak wind speed) and the number of intense tropical storms over the entire western North Pacific region increase significantly in global warming simulations.…”

“…Summertime extreme SWH is defined as the average of the highest 10% of the 3 hourly model output SWH for each summer (hereafter H top10 ). For extreme wind, we use a definition based on vector wind fields rather than the scalar winds used by Sasaki et al [2005b]. Since changes in a vector field can illustrate variations in wind direction, this approach is useful in the analysis of the associated physical mechanisms related to atmospheric variations.…”

“…Over the same period, Sasaki et al [2005a] found increasing swells in the summertime (June, July and August) in coastal waters south of Japan that were primarily due to the enhancement of tropical cyclones in the western North Pacific. Moreover, Sasaki et al [2005b] and Sasaki and Hibiya [2007] determined that the increase of summertime extreme wave heights was closely related to the duration of intense tropical cyclones (with central pressure below 980 hpa, ITCs).…”