What is the result of the conversion of shortwave solar radiation at Earth's surface?

• A. It is converted into longwave radiation (heat).
• B. It increases the surface albedo by reflecting more sunlight.
• C. It is transformed into ultraviolet radiation.
• D. It remains as visible light at the surface.

Answer: (A)

Energy from the sun that reaches the Earth's surface is mostly absorbed by the surface, warming it. That absorbed energy becomes heat within the surface, and as the surface gets warmer it radiates energy back into the atmosphere as longwave infrared radiation. So the key idea is that shortwave solar energy is converted to heat at the surface and then re-emitted as infrared radiation. Some sunlight is reflected, which relates to albedo, but the primary conversion described here is heat generation followed by longwave emission. The energy is not transformed into ultraviolet radiation, nor does it remain as visible light at the surface.