Scattered radiation is a phenomenon in which electromagnetic energy is redistributed in various directions due to the effects of air molecules and aerosol particles, or due to fluctuations in air density and unevenness. The distribution of scattered wave energy is related to the incident wavelength, intensity, and particle size, shape, and refractive index. They are called Rayleigh scattering (molecular scattering) and rice scattering of large particles.
The scattering of visible light by air molecules is Rayleigh scattering, and the light intensity is inversely proportional to the fourth power of the wavelength, so the sky is blue; cloud droplets and aerosol particles are rice scattering of visible light, and the light intensity is independent of wavelength, so the cloud is white. It is precisely because of the scattering effect of the atmosphere on the solar radiation meter that the sky becomes bright blue, otherwise it will be dark, and only one round of the sun will hang in the sky unusually brightly.
