Which region receives the highest solar input due to sun angle?

• A. Polar Regions
• B. Mid-latitudes
• C. Tropics
• D. High Latitudes

Answer: (C)

Solar input is highest where sunlight hits most directly. When the sun is high in the sky, its rays are more concentrated and pass through less atmosphere, delivering more energy per unit area. The tropics receive this direct sun because the subsolar point stays between the Tropic of Cancer and the Tropic of Capricorn all year, so the sun can be essentially overhead at solar noon. That posture gives the smallest solar zenith angle and the strongest insolation. In polar regions the sun stays low on the horizon, and in mid-latitudes the sun angle is intermediate, so the energy arriving at the surface is less. So, the tropics have the highest solar input due to sun angle.