Extreme waves due to climate change and its consequences continue to emerge at both regional and global scales.
A recent study published in the journal ‘Climate Dynamics’ has shown that the Indian Ocean, northern sector of the Arabian Sea, and central Bay of Bengal are likely to experience an increase in rough wave days in the near future. This information could help provide timely warning and planning to prevent major impacts on life and property, especially in coastal areas.
In a changing climate, extreme wave events can pose a tremendous impact on the livelihoods of the coastal population, infrastructure, and ocean-related activities. Observed variability and changes in extreme wave events, along with shifting storm intensity and tracks, can play a crucial role in shoreline changes, erosion rates, flooding episodes, and other related coastal hazards.
A team of scientists from the Department of Applied Sciences at the National Institute of Technology Delhi, the Indian Institute of Technology Kharagpur, and the Indian National Centre for Ocean Information Services in Hyderabad used COWCLIP2.0 datasets to project the likely future changes in extreme wave height indices over the Indian Ocean.
Their projections indicate that under a medium representative concentration pathway of greenhouse gases (RCP4.5), the regions over the eastern tropical Indian Ocean, northern sector of the Arabian Sea, and central Bay of Bengal showed a strong positive increase in rough wave days.
However, under a high-emission scenario corresponding to RCP8.5, a decreasing trend in rough wave days is likely over most regions in the Indian Ocean, with the exception of regions in the north Arabian Sea and extra-tropical regions beyond 48° S in the Southern Indian Ocean sector.
The research supported by the Science Research and Engineering Board, an attached institution of the Department of Science & Technology in India, could be useful to policymakers for both short and long-term planning that can benefit the coastal population.
Summary
- A study found that the Indian Ocean, northern sector of the Arabian Sea, and central Bay of Bengal are likely to experience an increase in rough wave days in the near future.
- The research used the COWCLIP2.0 datasets to project future changes in extreme wave height
- Under the climate scenario RCP4.5, there was a strong positive increase in rough wave days in the regions mentioned above
- However, under the high-emission scenario RCP8.5, there was a decreasing trend in rough wave days in most regions, with the exception of the north Arabian Sea and extra-tropical regions
- The study indicates that projected changes in the amplitude of extreme wave events in the Southern hemisphere are driven by changes in sea-level pressure gradient
- The research could be useful for short and long-term planning for the coastal population.
Figure: Climatology of extreme wave indices over the present-day period (1979–2004) and future time period (2081–2100) under RCP4.5 and RCP8.5 scenario
