Mishra et al. (2025) Future Projections of Marine Heatwaves in the Northern Indian Ocean Using the HighResMIP Models: Role of Horizontal Resolution and Percentile Thresholds

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: International Journal of Climatology
• Year: 2025
• Date: 2025-12-03
• Authors: Alok Kumar Mishra, Shivam Kesarwani, Suneet Dwivedi, Anand Singh Dinesh
• DOI: 10.1002/joc.70197

Research Groups

Not specified in the abstract.

Short Summary

This study investigates how model horizontal resolution and percentile thresholds influence marine heat wave (MHW) characteristics in the northern Indian Ocean using HighResMIP simulations. It finds that higher resolution improves MHW simulation and projects significant increases in MHW duration, intensity, and frequency, including the emergence of severe and extreme events, under the SSP5-8.5 scenario.

Objective

• To investigate how horizontal resolution and percentile thresholds used to define marine heat waves (MHWs) influence the characteristics (duration, maximum intensity, frequency) of these events over the northern Indian Ocean region, specifically the Arabian Sea (AS) and Bay of Bengal (BoB).

Study Configuration

• Spatial Scale: Northern Indian Ocean region, including the Arabian Sea and Bay of Bengal.
• Temporal Scale: Historical periods and future projections under the SSP5-8.5 scenario, focusing on near-future changes.

Methodology and Data

• Models used: High Resolution Model Intercomparison Project (HighResMIP) simulations.
• Data sources: HighResMIP model output.

Main Results

• Simulation of MHW characteristics improves with an increase in the model's horizontal resolution.
• MHW events in the Arabian Sea tend to be less frequent but of longer duration (10%–25%) compared to the Bay of Bengal region.
• MHW events defined using the 99th percentile threshold are of shorter duration (30%–50%) and higher intensity (70%–75%) compared to those defined by the 90th percentile threshold.
• Under the SSP5-8.5 scenario, future projections indicate MHW event duration, maximum intensity, and frequency will increase by up to 75%, 35%, and 98%, respectively, depending on the model and percentile threshold.
• Severe and extreme MHW events, which were absent during historical periods, are projected to significantly increase in the near future, becoming more frequent and of longer duration under global warming.
• A considerable inter-model variability exists in these projected changes, introducing uncertainty in future risk estimations.

Contributions

• Quantifies the influence of model horizontal resolution on the accuracy of MHW characteristic simulations.
• Demonstrates the impact of different percentile thresholds on the derived MHW characteristics (duration, intensity).
• Provides quantitative projections of future increases in MHW duration, intensity, and frequency under a high-emission scenario (SSP5-8.5).
• Highlights the projected emergence and significant increase of severe and extreme MHW events in the near future.
• Identifies inter-model variability as a key source of uncertainty, posing challenges for adaptation and mitigation strategies.

Funding

Not specified in the abstract.

Citation

@article{Mishra2025Future,
  author = {Mishra, Alok Kumar and Kesarwani, Shivam and Dwivedi, Suneet and Dinesh, Anand Singh},
  title = {Future Projections of Marine Heatwaves in the Northern Indian Ocean Using the <scp>HighResMIP</scp> Models: Role of Horizontal Resolution and Percentile Thresholds},
  journal = {International Journal of Climatology},
  year = {2025},
  doi = {10.1002/joc.70197},
  url = {https://doi.org/10.1002/joc.70197}
}