The correct option is The supply of moisture is cut off..
Explanation
Tropical cyclones act as atmospheric heat engines that derive their energy primarily from the latent heat of condensation. This energy is released when warm, moist air rises from the ocean surface and condenses to form clouds. The sustainability of the system depends entirely on the continuous input of moisture from warm ocean waters.
Detailed Analysis
- The supply of moisture is cut off. is Correct: Upon making landfall, the cyclone is physically separated from its primary energy source-the warm ocean water. Without the continuous evaporation and supply of moisture, the release of latent heat stops. Starved of its fuel, the storm system weakens rapidly and dissipates.
- The friction over land reduces wind speed immediately. is Incorrect: While the increased surface roughness and friction over land do act to reduce wind speeds and disrupt the airflow structure, this is a secondary factor. The primary cause of the system's death is the removal of its energy source (moisture), not merely mechanical friction.
- The land surface temperature is lower than the ocean. is Incorrect: The dissipation is not driven by the surface temperature of the land itself. Even if the land surface is hot, it lacks the abundant moisture required to fuel the latent heat release.
- The Coriolis force is weaker over land. is Incorrect: The Coriolis force is a function of latitude and Earth's rotation. It remains constant at a specific latitude regardless of whether the surface below is land or water.
Key Takeaway: The lifespan of a tropical cyclone is dictated by its access to warm, moist air; once the supply of moisture is cut off after landfall, the mechanism of latent heat release fails, causing the storm to die out.