Analysis of temporal and spatial characteristics of waves in the Indian Ocean based on ERA-40 wave reanalysis. (February 2017)

• Record Type: Journal Article
• Authors: Zheng, Chong Wei; Li, Chong Yin
• Is Part Of: Applied ocean research. Volume 63(2017:Oct.)
• Page Start: 217
• Page End: 228
• Publication Date: 2017-02
• Subjects: Indian ocean -- Swell -- Interannual variability -- Interdecadal variability -- Intraseasonal oscillation -- Propagation; Ocean engineering -- Periodicals; 620.416205
• DOI: 10.1016/j.apor.2017.01.014
• Languages: English
• ISSNs: 0141-1187

Abstract

Highlights: Swell in the roaring forties and tropical waters have a common period of 9.8-10.4 years on the interdecadel scale. The wind and swell in the roaring forties and swell in the tropical waters have a weekly oscillation. Swell of the roaring forties needs about 30 h to fully response to the wind of this region. It needs about 132–138 h that the swell propagating from roaring forties to the tropical waters. The wind speed and wave height in the roaring forties and tropical waters mainly exhibit a significant increasing trend for the past 45 years. Abstract: Based on the 45-year (09/1957-08/2008) European Centre for Medium-Range Weather Forecasts (ECMWF) Reanalysis (ERA-40) wave reanalysis dataset, this study analyzes interannual and interdecadal variabilities and intraseasonal oscillations of sea surface wind speed (WS), wind sea wave height ( H w ), swell wave height ( H s ) and significant wave height ( Hs ) in the Roaring Forties and tropical waters of the Indian Ocean, to determine swell propagation characteristics. The results show: (1) monthly variabilities of H s in the Roaring Forties are in good agreement with those in tropical waters of the Indian Ocean; swell plays a dominant role in mixed waves throughout most of the Indian Ocean; and WS, H w, H s, and Hs exhibit a significant increasing trend over the 45-year study period. (2) H s in the Roaring Forties and tropical waters of the Indian Ocean share a common period of 9.8–10.4 years on an interdecadal scale; and WS and H s in the Roaring Forties and H s in the tropical waters of the Indian Ocean share a common period of approximately 8 days (weekly oscillation) on an intraseasonal scale. (3) Swell of the Roaring Forties needs approximately 30 h to fully respond to the wind in this region. Approximately 84 h are required for H s to propagate from the Roaring Forties to the tropical waters of the south Indian Ocean, while it takes approximately 132–138 h for H s to propagate from the Roaring Forties to the tropical waters of the north Indian Ocean.