Propagation of Atlantic Ocean swells in the north Indian Ocean: a case study

Abstract

An analysis of altimeter significant wave height data of May 2007 revealed the occurrence of an extreme weather event off southern tip of South Africa in the Atlantic Ocean, and generation of a series of very high swells at 40° S. These swells propagated towards northeast and broke over La Réunion island in the Indian Ocean on 12 May 2007. The wave model WAVEWATCH III was used to study the propagation of these swells in the Indian Ocean. The model was validated for the Indian Ocean using moored buoy data at 12 locations and merged altimeter wave data. The wave model accurately reproduced the event of May 2007. Swell heights, of the order of 15.0 m, at the generation area reduced to 6.0 m near La Réunion island. This study shows that the swells generated in the Roaring Forties of the Atlantic Ocean (between 15° to 80° E longitude) propagate in the NE/NNE direction towards the north Indian Ocean, and wave characteristics of the Arabian Sea are least influenced compared to that of Bay of Bengal, when swells from the Atlantic Ocean enter the Indian Ocean. The double peak spectrum extracted for the Bay of Bengal indicates that one of the peaks is due to swells generated off southern tip of South Africa

Propagation Route and Speed of Swell in the Indian Ocean

“…A similar phenomenon was also reported by Alves (). Our results agree with those of Samiksha et al () and Alves (2006), although the northward propagation is more obvious in our analysis. Aboobacker et al () and Glejin et al () determined that the predominant northward swell propagation (coming from the south) in the midwest of the Arabian Sea is disrupted during DJF and that the Shamal swells play an important role in this disruption.…”

“…The propagation route of swells from region D is significantly affected by the terrain of Australia. Samiksha et al (2012) found that a series of very high swells that originated at 408S, off the southern tip of South Africa, propagated to the northeast and broke over the island of Reunion in the subtropical waters of the southern Indian Ocean. A similar phenomenon was also reported by Alves (2006).…”

Assessment of the wave potential at selected hydrology and coastal environments around a tropical island, case study: Mauritius

“…The geographic location of Reunion Island reduces the wave energy potential of the coasts of Mauritius. Swell heights of the order of 15.0 m, at the generation site is reduced to 6.0 m near Reunion Island [26]. It is revealed that the eastward propagating extratropical South Atlantic swell energy spreads through the entire Indian Ocean, attaining the coasts of Thailand, Indonesia and southwestern Australia and penetrating as far as the Tasman Sea [25].…”

Wave energy dissipation in the mangrove vegetation off Mumbai, India

“…Mumbai (Aboobacker et al, 2011, Samiksha et al, 2012, Sabique et al, 2012. The outer domain was set for Wavewatch III Ocean Sci.…”