Energy: Solar radiation energy.

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Atmospheric transmission: part of it is attenuated by the scattering and absorption of particles in the atmosphere. Energy with wavelength in the atmospheric window can pass through the atmosphere and reach the surface after atmospheric attenuation.

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Interaction with the surface: When energy with different wavelengths reaches the surface, it is selectively reflected, absorbed, transmitted and refracted.

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Passing through the atmosphere again: The energy containing different spectral responses of ground objects is absorbed by the atmosphere again and attenuated by scattering. It not only weakens the intensity of ground radiation received by the sensor, but also reduces the contrast of remote sensing images due to scattered skylight, resulting in radiation, geometric distortion and image blurring of remote sensing data, which directly affects the clarity, quality and interpretation accuracy of images.

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Remote sensing system: records radiation values through remote sensing system.

The signal received by the remote sensor includes two parts:

One is the distance radiation of the atmosphere itself as a reflector (scatterer), which does not contain the information of ground objects.

The second is the contribution of the ground target to the remote sensor, which includes four parts:

(1) The light is directly incident on the ground and reflected to the remote sensor through the ground.

(2) The light reaches the ground through atmospheric scattering, and directly reflects to the part of the remote sensor through the ground.

(3) Light is directly incident on the ground, reflected by the ground and scattered by the atmosphere to the remote sensor.

(4) Light is scattered to the ground through the atmosphere, reflected by the ground, scattered by the atmosphere to the part of the remote sensor, and the ground and the atmosphere are mutually scattered for many times to reach the part of the remote sensor.

As shown in the figure: