Final answer:
Approximately 30% of solar radiation reaching Earth is reflected directly back into space primarily by clouds and snow. This reflected amount depends on the albedo of Earth's surface and atmosphere. Absorption and reflection of this energy influence Earth's energy balance and temperature.
Step-by-step explanation:
The concept of albedo relates to how much sunlight is reflected or scattered directly back into space without being absorbed by Earth's surface or atmosphere. The Earth has an overall albedo of about 30%, which means that approximately 30% of the incoming solar radiation is reflected back into space. The remaining 70% is absorbed by Earth's land, water, and atmosphere, where it contributes to warming the planet.
When considering a uniform solar power arriving at Earth's topmost atmosphere of 1,360 W/m², around 29.3% of this energy is reflected back due to clouds, snow, and other terrain features with different albedos. Consequently, about 960 W/m² of solar energy is absorbed over the projected area of Earth when faced directly towards the sun. This incident energy contributes to Earth's overall energy balance and equilibrium temperature.