why is the angle of rays of sunlight so important in determining the amount of energy collected by the earth
http://www.instruction.greenriver.edu/physics/intensity/intensityangle.html
why is the angle of rays sunlight so important
The angle at which sunlight reaches the Earth's surface is crucial in determining the amount of energy collected because it affects the intensity or concentration of solar energy. When sunlight reaches the Earth, it is more spread out and less concentrated if it strikes at a low angle. On the other hand, when sunlight strikes at a higher angle, it is concentrated over a smaller area, leading to higher energy levels.
To understand why the angle of sunlight is important, we need to consider a concept called "solar zenith angle." This angle measures the angle between the direction of the Sun and a line perpendicular to the Earth's surface. When the Sun is directly overhead (at the zenith), the solar zenith angle is 0 degrees, and the sunlight strikes the Earth's surface vertically. As the Sun moves away from the zenith, the solar zenith angle increases, reflecting a lower angle of incidence.
The solar zenith angle affects the intensity of sunlight reaching the Earth's surface primarily due to two reasons:
1. Solar path length: When sunlight enters the atmosphere at a lower angle, it has to pass through a greater thickness of the Earth's atmosphere. The atmosphere scatters and absorbs a portion of the sunlight, causing some energy loss. Thus, the longer the path length, the more scattering and absorption occur, reducing the energy received at the surface. In contrast, when sunlight strikes at a higher angle, it doesn't have to traverse through as much atmosphere, resulting in less scattering and absorption.
2. Surface area coverage: Sunlight striking the Earth's surface at a lower angle covers a larger surface area. The same amount of energy is spread out over a larger area, resulting in lower energy concentration. However, when sunlight strikes at a higher angle, it covers a smaller surface area, leading to higher energy concentration.
Overall, the angle of sunlight is crucial in determining the amount of energy collected by the Earth because it influences the concentration and intensity of solar energy reaching the surface. By considering the solar zenith angle, scientists and researchers can understand and predict variations in solar energy availability under different conditions and locations on Earth.