High-resolution modeling reveals how monsoons, eddies, and equatorial forces shape the movement of water, heat, and freshwater—critical for climate and coastal forecasting.

Reporting by Helen Hill for MITgcm

A new study led by Kunal Madkaiker of the Indian Institute of Technology Delhi utilizes the MIT General Circulation Model (MITgcm) to simulate, with unprecedented detail, the movement of volume, freshwater, and heat along India’s coastline throughout the year. Published in Ocean Science in 2024, the research provides a clearer picture of the seasonal dynamics that influence regional climate, fisheries, and ocean health.

India’s coastal waters are shaped by powerful monsoon winds, reversing currents, and remote equatorial influences. Yet, until now, the fine-scale processes driving these patterns have been difficult to model accurately. Madkaiker’s team tackled this challenge using MITgcm.

“MITgcm allowed us to resolve the complex interplay of monsoon-driven currents, eddies, and boundary flows at a scale that captures real-world variability,” says Madkaiker.

The model was validated against satellite and in situ data, including ARGO floats and RAMA buoys, ensuring realistic simulation of temperature, salinity, and current patterns.

The study revealed distinct behaviors on India’s east and west coasts. On the east, the East India Coastal Current (EICC) showed strong seasonal reversals—flowing northward during the southwest monsoon and southward during the northeast monsoon. On the west, the West India Coastal Current (WICC) exhibited more chaotic behavior.

Freshwater transport, though a smaller component, showed important seasonal trends. On the east coast, freshwater and volume transport peaked together during the monsoon. On the west coast, they were inversely related, suggesting different controlling mechanisms.

Heat transport was also significant. Both the Arabian Sea and Bay of Bengal acted as heat sources in summer and sinks in winter, with stronger north-south heat movement in the Arabian Sea.

The model highlighted the role of mesoscale eddies—swirling ocean features that redistribute heat and freshwater, especially along the coast. It also showed how remote equatorial signals can propagate thousands of kilometers to influence coastal currents.

“These findings underscore the importance of both local and remote drivers in shaping India’s coastal ocean,” says Madkaiker.

By capturing these dynamics, the study lays the groundwork for improved regional climate models and coastal forecasting systems. It also demonstrates the power of MITgcm as a tool for resolving fine-scale ocean processes in complex environments.

Madkaiker hopes that future studies will build on this framework to explore biogeochemical cycles and the impacts of climate change. “With better data and models, we can better understand and protect our coastal systems,” he says.

To find out more about this work​ contact Kunal

Story image: Courtesy the researcher.

About the Researcher

Kunal Madkaiker is a PhD scholar from the Indian Institute of Technology Delhi, India. He has been using MITgcm for his doctoral research since 2019.

 

This Month’s Featured Publication

Other New Publications last month

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