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How do tropical cyclones gain energy from warm ocean water?

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volcanology — Earth sciences Geologist using a rock hammer to sample active pahoehoe lava for geochemical analysis on the Kilauea volcano, Hawaii, June 26, 2009.

Tropical cyclones derive their energy from the transfer of heat and water vapour from the warm ocean surface to the atmosphere, a process driven primarily by evaporation.1

As this warm, moist air rises, it expands and cools, eventually reaching saturation. This leads to the condensation of water vapour, which releases latent heat into the storm's core. This warming makes the rising air more buoyant, further enhancing its upward movement and lowering the atmospheric pressure at the storm's centre. The resulting pressure drop increases surface winds, which in turn accelerates the transfer of heat and moisture from the ocean, creating a self-reinforcing positive feedback mechanism.1

For this process to sustain a cyclone, the ocean surface typically requires temperatures exceeding 26 °C (about 79 °F) within the upper 60 metres of water. If a storm moves over cooler water or if turbulence mixes cooler water from deeper layers to the surface, the fuel supply is cut off, causing the cyclone to lose intensity.231