A recent study of extreme wave events indicates that the Indian Ocean, the northern sector of the Arabian Sea and the central Bay of Bengal are likely to experience an increase in the number of rough wave days in the near future. It could help early warning and planning to avoid major impacts on life and property, especially in coastal areas.
In a changing climate, extreme waves, which have been recorded quite often in recent times, can have a huge impact on coastal livelihoods, infrastructure and ocean-related activities. Observed variability and changes in extreme wave events, along with shifts in storm intensity and tracks, may play a major role in shoreline changes, erosion rates, inundation, and other related coastal hazards.
Extreme waves caused by climate change and its consequences continue to occur on a regional and global scale. A better understanding of future projected changes in the amplitude of high-frequency extreme waves is therefore essential for early warning and coastal planning and management. A team of scientists from the Department of Applied Sciences, National Institute of Technology Delhi; Indian Institute of Technology Kharagpur; and the Indian National Center for Ocean Information Services, Hyderabad, projected likely future changes in extreme wave height indices over the Indian Ocean.
In his research published in the journal “Climate Dynamics,” Springer recently used the COWCLIP2.0 datasets to show that the large-scale distribution in the future wave climate may differ significantly from the present. Future projections by scientists Divya Sardan and Prashant Kumar of the Department of Applied Sciences, NIT Delhi, Prasad K. Bhaskaran of the Department of Ocean Engineering and Naval Architecture, IIT Kharagpur and T. M. Balakrishnan Nair of ESSO-INCOIS Hyderabad suggest that under the RCP4.5 scenario (medium representative GHG concentration pathway) regions over the eastern tropical Indian Ocean, the northern sector of the Arabian Sea, and the central Bay of Bengal showed a strong positive increase in rough wave days.
High-frequency extreme wave events in the Southern Hemisphere
However, under the high emission scenario corresponding to RCP8.5, a decreasing trend in rough wave days is likely in most regions in the Indian Ocean, except for regions in the northern Arabian Sea and the extratropical regions beyond 48°S in the southern Indian Ocean sector. Changes in high wave days are projected to intensify over the southern Indian Ocean under the RCP 4.5 and 8.5 scenarios, and wave-spell-storm duration is found to intensify over the northern Arabian Sea and Bay of Bengal, southeastern Indian Ocean, and southern Indian Ocean. under the RCP8.5 forced scenario.
The study suggests that projected changes in the amplitude of high-frequency extreme wave events in the Southern Hemisphere are driven by changes in the sea level pressure gradient, which is consistent with Southern Annular Mode (SAM) projections for the 21st century. time. Research supported by the Scientific Research and Engineering Board (SERB), an affiliated institution of the Department of Science and Technology (DST), Government of India, can be immensely useful to policy makers and decision-makers in both the short and long term. planning that can benefit coastal residents.
