Earth and Planetary Science

Marine Heatwaves and Cyclone Interactions in the North Indian Ocean: A Tale of Shaheen and Gulab

Tarakeshwar Pukkalla

Department of Meteorology and Oceanography, Andhra University, Visakhapatnam, Andhra Pradesh 530003, India

Muni Krishna Kailasam

Department of Meteorology and Oceanography, Andhra University, Visakhapatnam, Andhra Pradesh 530003, India

DOI: https://doi.org/10.36956/eps.v4i2.2041

Received: 22 April 2025 | Revised: 8 September 2025 | Accepted: 18 September 2025 | Published Online: 30 September 2025

---

Abstract

Tropical cyclones (TCs) are among the most devastating natural hazards, and their development can be significantly influenced by marine heatwaves (MHWs)—periods when sea surface temperatures (SSTs) rise 3–4 °C above average for at least five days. This study investigates the interaction between TCs Gulab and Shaheen and MHW conditions in the North Indian Ocean during September–October 2021. Using data from NOAA‑OISST and HYCOM model outputs, along with the Marine Heatwave Tracker, we mapped the timeline of MHWs relative to the formation and intensification of these cyclones. TC Gulab originated in the Bay of Bengal and later redeveloped as TC Shaheen in the Arabian Sea—an uncommon occurrence during the southwest monsoon season. On average, 1–2 cyclones form annually in the Arabian Sea, and about 48.5% dissipate without making landfall. However, TC Shaheen intensified into a Severe Cyclonic Storm (SCS) and made landfall on Oman’s coast, where persistent MHWs were observed. The study suggests that elevated SSTs due to MHWs played a significant role in sustaining and intensifying the storm system. These findings highlight the importance of understanding oceanic thermal anomalies in assessing cyclone behavior and potential landfall impacts, especially in the context of a warming climate and increasing frequency of extreme marine heat events.

Keywords: Marine Heatwave; Cyclone; Mixed Layer Depth

---

References

[1] Darmaraki, S., Somot, S., Sevault, F., et al., 2019. Future Evolution of Marine Heatwaves in the Mediterranean Sea. Climate Dynamics. 53, 1371–1392. DOI: https://doi.org/10.1007/s00382-019-04661-z

[2] Hobday, A.J., Alexander, L.V., Perkins, S.E., et al., 2016. A Hierarchical Approach to Defining Marine Heatwaves. Progress in Oceanography. 141, 227–238. DOI: https://doi.org/10.1016/j.pocean.2015.12.014

[3] Pearce, A.F., Lenanton, R., Jackson, G., et al., 2011. The ‘Marine Heat Wave’ off Western Australia During the Summer of 2010/2011. Fisheries Research Report No. 221. Government of Western Australia Department of Fisheries: North Beach, Western Australia, pp. 1–40.

[4] Jacox, M.G., Alexander, M.A., Amaya, D., et al., 2022. Global Seasonal Forecasts of Marine Heatwaves. Nature. 604, 486–490. DOI: https://doi.org/10.1038/s41586-022-04573-9

[5] Kumar, S., Chakraborty, A., Chandrakar, R., et al., 2023. Analysis of Marine Heatwaves over the Bay of Bengal During 1982–2021. Scientific Reports. 13, 14235. DOI: https://doi.org/10.1038/s41598-023-39884-y

[6] Li, Z., Wu, G., Xu, C., et al., 2024. Summer Marine Heatwaves in the Tropical Indian Ocean Associated with an Unseasonable Positive Indian Ocean Dipole Event. Frontiers in Marine Science. 11, 1425813. DOI: https://doi.org/10.3389/fmars.2024.1425813

[7] Kuttippurath, J., Maishal, S., Anjaneyan, P., et al., 2023. Recent Changes in Atmospheric Input and Primary Productivity in the North Indian Ocean. Heliyon. 9(7), e17940. DOI: https://doi.org/10.1016/j.heliyon.2023.e17940

[8] Krishnapriya, M.S., Varikoden, H., Anjaneyan, P., et al., 2023. Marine Heatwaves During the Pre-Monsoon Season and Their Impact on Chlorophyll-a in the North Indian Ocean in 1982–2021. Marine Pollution Bulletin. 197, 115783. DOI: https://doi.org/10.1016/j.marpolbul.2023.115783

[9] Akhila, R.S., Kuttippurath, J., Sarojini, B.B., et al., 2022. Observed Tropical Cyclone-Driven Cold Wakes in the Context of Rapid Warming of the Arabian Sea. Journal of Operational Oceanography. 16(3), 236–251. DOI: https://doi.org/10.1080/1755876X.2022.2068260

[10] Krishna, K.M., 2009. Intensifying Tropical Cyclones over the North Indian Ocean During Summer Monsoon—Global Warming. Global and Planetary Change. 65(1–2), 12–16. DOI: https://doi.org/10.1016/j.gloplacha.2008.10.007

[11] Nadimpalli, R., Mohanty, S., Pathak, N., et al., 2021. Understanding the Characteristics of Rapid Intensity Changes of Tropical Cyclones over North Indian Ocean. SN Applied Sciences. 3, 68. DOI: https://doi.org/10.1007/s42452-020-03995-2

[12] Rathore, S., Goyal, R., Jangir, B., et al., 2022. Interactions Between a Marine Heatwave and Tropical Cyclone Amphan in the Bay of Bengal in 2020. Frontiers in Climate. 4, 861477. DOI: https://doi.org/10.3389/fclim.2022.861477

[13] Shenoi, S.S.C., Shankar, D., Shetye, S.R., 2002. Differences in Heat Budgets of the Near-Surface Arabian Sea and Bay of Bengal: Implications for the Summer Monsoon. Journal of Geophysical Research. 107(C6), 1–14. DOI: https://doi.org/10.1029/2000JC000679

[14] Kumar, S., Lal, P., Kumar, A., 2020. Turbulence of Tropical Cyclone ‘Fani’ in the Bay of Bengal and Indian Subcontinent. Natural Hazards. 103, 1613–1622. DOI: https://doi.org/10.1007/s11069-020-04033-5

[15] Murty, T., El-Sabh, M., 1984. Cyclones and Storm Surges in the Arabian Sea: A Brief Review. Deep Sea Research Part A Oceanographic Research Papers. 31(6–8), 665–670

[16] Najah, A., van der Merwe, R., Al Shehhi, M.R., 2025. Review of Tropical Cyclones Impacting the Western Arabian Sea and Oman. Journal of Operational Oceanography. 18(1), 21–39. DOI: https://doi.org/10.1080/1755876X.2024.2444753

[17] Naskar, P.R., Pattanaik, D.R., 2023. Variations of Central Pressure of Intense Tropical Cyclones over the Bay of Bengal with Latent Heat Flux and Other Parameters. Journal of Earth System Science. 132, 44. DOI: https://doi.org/10.1007/s12040-023-02065-6

[18] Yanase, W., Satoh, M., Taniguchi, H., et al., 2012. Seasonal and Intraseasonal Modulation of Tropical Cyclogenesis Environment over the Bay of Bengal During the Extended Summer Monsoon. Journal of Climate. 25(8), 2914–2930. DOI: https://doi.org/10.1175/JCLI-D-11-00208.1

[19] Roxy, M., Tanimoto, Y., 2007. Role of SST over the Indian Ocean in Influencing the Intraseasonal Variability of the Indian Summer Monsoon. Journal of the Meteorological Society of Japan Series II. 85(3), 349–358. DOI: https://doi.org/10.2151/jmsj.85.349

[20] Jaiswal, N., Jishad, M., Deb, S.K., et al., 2023. Analysis of Atmospheric and Oceanic Conditions During Unusual Occurrence of Tropical Cyclone Gulab and Shaheen in North Indian Ocean. Journal of Earth System Science. 132, 109. DOI: https://doi.org/10.1007/s12040-023-02129-7

[21] Levitus, S., Antonov, J.I., Boyer, T.P., et al., 2012. World Ocean Heat Content and Thermosteric Sea Level Change (0–2000 m), 1955–2010. Geophysical Research Letters. 39(10), L10603. DOI: https://doi.org/10.1029/2012GL051106

[22] Oliver, E.C.J., 2019. Mean Warming Not Variability Drives Marine Heatwave Trends. Climate Dynamics. 53, 1653–1659. DOI: https://doi.org/10.1007/s00382-019-04707-2

[23] Oliver, E.C.J., Donat, M.G., Burrows, M.T., et al., 2018. Longer and More Frequent Marine Heatwaves Over the Past Century. Nature Communications. 9, 1324. DOI: https://doi.org/10.1038/s41467-018-03732-9

[24] Elzahaby, Y., Schaeffer, A., Roughan, M., et al., 2021. Oceanic Circulation Drives the Deepest and Longest Marine Heatwaves in the East Australian Current System. Geophysical Research Letters. 48(17), e2021GL094785. DOI: https://doi.org/10.1029/2021GL094785

[25] Elzahaby, Y., Schaeffer, A., Roughan, M., et al., 2022. Why the Mixed Layer Depth Matters When Diagnosing Marine Heatwave Drivers Using a Heat Budget Approach. Frontiers in Climate. 4, 838017. DOI: https://doi.org/10.3389/fclim.2022.838017

[26] Li, Y., Ren, G., Wang, Q., et al., 2023. Record-Breaking Marine Heatwave in Northern Yellow Sea During Summer 2018: Characteristics, Drivers and Ecological Impact. Science of The Total Environment. 904, 166385. DOI: https://doi.org/10.1016/j.scitotenv.2023.166385

[27] Choi, H.Y., Park, M.S., Kim, H.S., et al., 2024. Marine Heatwave Events Strengthen the Intensity of Tropical Cyclones. Communications Earth & Environment. 5, 69. DOI: https://doi.org/10.1038/s43247-024-01239-4

[28] Pun, I.F., Hsu, H.H., Moon, I.J., et al., 2023. Marine Heatwave as a Supercharger for the Strongest Typhoon in the East China Sea. npj Climate and Atmospheric Science. 6, 128. DOI: https://doi.org/10.1038/s41612-023-00449-5

[29] Cione, J.J., Uhlhorn, E.W., 2003. Sea Surface Temperature Variability in Hurricanes: Implications With Respect to Intensity Change. Monthly Weather Review. 131, 1783–1796. DOI: https://doi.org/10.1175//2562.1

[30] Zhang, H., He, H.L., Zhang, W.Z., et al., 2021. Upper Ocean Response to Tropical Cyclones: A Review. Geoscience Letters. 8, 1. DOI: https://doi.org/10.1186/s40562-020-00170-8

[31] Elzahaby, Y., Schaeffer, A., 2019. Observational Insight Into the Subsurface Anomalies of Marine Heatwaves. Frontiers in Marine Science. 6, 745. DOI: https://doi.org/10.3389/fmars.2019.00745

[32] Jackson, J.M., Johnson, G.C., Dosser, H.V., et al., 2018. Warming From Recent Marine Heatwave Lingers in Deep British Columbia Fjord. Geophysical Research Letters. 45(18), 9757–9764. DOI: https://doi.org/10.1029/2018GL078971

[33] Heidemann, H., Ribbe, J., 2019. Marine Heatwaves and the Influence of El Niño Off Southeast Queensland, Australia. Frontiers in Marine Science. 6, 56. DOI: https://doi.org/10.3389/fmars.2019.00056

[34] Intergovernmental Panel on Climate Change (IPCC), 2018. Strengthening the Global Response in the Context of Sustainable Development and Efforts to Eradicate Poverty. In: Masson-Delmotte, V., Zhai, P., Pörtner, H.O., et al. (eds.). Global Warming of 1.5°C. An IPCC Special Report on the Impacts of Global Warming of 1.5°C Above Pre-Industrial Levels and Related Global Greenhouse Gas Emission Pathways. World Meteorological Organization: Geneva, Switzerland. pp. 313–444.

[35] Vellore, R.K., Deshpande, N., Priya, P., et al., 2020. Extreme Storms. In: Krishnan, R., Sanjay, J., Gnanaseelan, C., et al. (eds.). Assessment of Climate Change Over the Indian Region. Springer: Singapore. pp. 155–173. DOI: https://doi.org/10.1007/978-981-15-4327-2_8