Final answer:
The sun is the power source that drives convection within the atmosphere and ocean, causing variations in temperature and density that lead to the movement of air and water masses.
Step-by-step explanation:
The power that drives convection within the atmosphere and ocean is the sun. Convection is driven by the large-scale flow of matter, primarily influenced by the heating effects of the sun which causes variations in temperature and density that result in the movement of air and water masses. On Earth, this manifests as atmospheric circulation caused by the flow of hot air from the tropics to the poles and the flow of cold air from the poles toward the tropics. Similarly, ocean currents facilitate the transfer of energy across the globe, also driven by the energy from the sun.
While mechanisms like conduction are critical for heat transfer, such as in metal objects, convection in the climate system is heavily dependent on solar energy that warms the surface and leads to rising hot air and sinking cooler air as part of convective cycles.