Extreme events of 2024 in the Tropical Indian Ocean: leveraging heterogeneous multi-platform observations from NODC-INCOIS

Frequent tropical cyclones in the North Indian Ocean significantly disrupt coastal and marine environments. This study integrates multi-platform datasets – including satellites, Argo floats, moored buoys, and tide gauges – to analyze the ocean‒atmosphere response to four 2024 cyclones: Remal, Asna, Dana, and Fengal. Satellite and Argo data revealed marked sea surface cooling, elevated chlorophyll-a, and thermocline uplift. These changes were driven by vertical mixing and upwelling, with Ekman pumping velocities exceeding 0.3 m/s. Notably, subsurface salinity exhibited greater sensitivity to wind-driven Ekman pumping than temperature. Simultaneously, the moored buoys recorded extreme pressure drops and wind speeds surpassing 20 m/s. The coastal impacts were severe; wave rider buoys recorded 2–3 m swells, while tide gauges measured storm surges near 500 cm during Remal and Asna. Conversely, Cyclone Fengal produced a rare negative surge. By synthesizing heterogeneous observation systems, this research highlights a consistent correlation between high winds, low pressure, subsurface thermal shifts, and coastal surges. This integrated approach is vital for understanding complex air‒sea interactions and improving future cyclonic predictability.