Certified Landscape Irrigation Auditor

What factors can influence the intensity of sunlight?

1. Wind speed and direction

2. Season, cloud cover, altitude, and shade

3. Humidity and temperature

4. Soil drainage

The correct answer is: Season, cloud cover, altitude, and shade

The intensity of sunlight received at a particular location is affected by several environmental factors, which is why the choice discussing season, cloud cover, altitude, and shade is the most accurate. Seasons play a significant role due to the tilt of the Earth's axis, which affects the angle at which sunlight strikes the surface. During summer, the sun is higher in the sky, resulting in more direct sunlight and increased intensity compared to winter when the sun is lower in the sky. Cloud cover can significantly diminish sunlight intensity as clouds scatter and absorb sunlight, leading to reduced light reaching the ground. The thickness and type of cloud cover will influence the amount of light that penetrates. Altitude also impacts sunlight intensity; at higher elevations, the atmosphere is thinner, which typically allows for more intense sunlight due to reduced scattering and absorption of solar radiation. Shade, whether from trees, buildings, or other structures, reduces direct sunlight exposure in specific areas, influencing the overall intensity of sunlight that plants or surfaces receive. In contrast, wind speed and direction, humidity, temperature, and soil drainage do not directly affect the intensity of sunlight itself. While they can influence weather conditions and ecosystems in various ways, they do not change how much sun reaches a location at a given time.