01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-05-0063 |
| Title of Abstract | Historical simulation and future projection of marine heatwaves over the Northern Tropical Indian Ocean using CMIP6 models. |
| Authors | Nandana P K*, Dr. Hamza Varikoden, Dr. Babu C A |
| Organisation | Cochin University of Science and Technology |
| Address | Punneth methil, Muttumkunnu, Ramanattukara P O, Kozhikode, Kerala Ramanattukara, Kerala, India Pincode: 673633 E-mail: npk3696@gmail.com |
| Country | India |
| Presentation | Poster |
| Abstract | Marine Heatwaves (MHWs) are extreme events of unusually high ocean temperatures threatening marine life, ecosystems and coastal communities. This study analyses MHW events and their characteristics, such as duration and intensity, over the North Tropical Indian Ocean for the historical (1982 to 2014) and future projection (2015-2100) period using CMIP6 simulations. NOAA OISST data was utilised for observational comparison. During the historical period, 50 to 90 events were detected with durations of 5 to 15 days. The average SST ranges from 27.5° to 31°C with peak SST values up to 33.5°C. Models tend to overestimate duration and underestimate the number of events, simulating longer but less frequent MHWs. Model performance was evaluated using Taylor diagrams and Taylor skill score. Based on Taylor skill score, IPSL-CM6A-LR, IPSL-CM6A-LR-INCA, and GFDL-CM4 models are considered the best performing models. Multi-model ensemble was prepared based on the three selected CMIP6 models under different SSP scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5). This reveals a near-permanent MHW state due to the occurrence of multi-year MHWs by the end of the century, by using a fixed baseline. Average SSTs range from 27° to 30.5°C (near-future) to 33.5°C (far-future). The central-west Equatorial Indian Ocean is projected to be a hotspot region with frequent, longest, and most intense MHWs. In contrast, the East equatorial Indian Ocean and Northern Arabian Sea (except the Gulf of Oman) show comparatively lower intensification in SST. The extreme scenario of far-future shows a 2.5°C increase in average SST over historical levels, with peak SST reaching an alarming value of 36.5°C, which was 3°C more than the historical maximum. All metrics, except the number of events, show an increasing trend with increasing emissions, highlighting the critical role of controlling emissions in regulating the occurrence of extreme events. |
| Are you part of IIOE-2 endorsed project | no |
| Keywords | MHW, CMIP6, Indian Ocean, Future projection |
| For Awards | yes |
| Date Of Birth | 11-01-2003 |
| ECSN Registration Number | IIOE2-ECSN-0216 |