Diffuse radiation refers to the radiation that is absorbed from the sun after being reflected and scattered by the earth and atmosphere.
The primary means of energy exchange on the surface of the Earth is solar radiation, which also has a significant impact on how productive ecosystems are. They are classified as photosynthetically active radiation (PAR), which is the primary energy source for plant photosynthesis, and range in wavelength from 400 to 700 nm. The leaves of the plant canopy can be classified as sunny leaves and shaded leaves based on their ability to absorb solar energy. Sunlit leaves receive direct and diffuse radiations, and photosynthesis is light-saturated for a canopy with a complex vertical structure, whereas shaded leaves receive only diffuse radiation, and photosynthesis is typically light-limited.
What is the Difference Between Direct and Diffuse Radiation?
Solar radiation that travels directly from the sun to the earth’s surface is referred to as direct radiation, sometimes known as beam radiation or direct beam radiation.
On the other hand, diffuse radiation refers to sunlight that has nevertheless reached the earth’s surface despite being scattered by molecules and other atmospheric constituents.
Simply said, diffuse radiation takes a considerably more erratic route than direct radiation, which has a clear direction. An object can block all of the radiation’s rays at once when it is direct since they are all moving in the same direction. As a result, it should be emphasized that shadows only appear when direct radiation is obstructed.
When the sky is clear and the sun is at its highest point in the sky, direct radiation accounts for about 85% of the total insolation that hits the ground, while diffuse radiation makes up the remaining 15%. The percentage of diffuse radiation keeps rising as the sun descends into the sky, reaching 40% when it is 10° above the horizon.
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