Atmospheric visibility is an important indicator of atmospheric transparency, which refers to the maximum horizontal distance from the ground at which a person with normal vision can see the outline of a target clearly under certain weather conditions. This concept is not only related to the fields of aviation, navigation and land transport, but also has a direct connection with high altitude photography, astronomical observation and military operations. 

Measurement of atmospheric visibility

Measuring atmospheric visibility can be done visually or by relying on a variety of special measuring instruments, such as atmospheric neurotransmitters and automatic laser visibility meters. With the development of technology, the University of Science and Technology of China (USTC) has developed a digital camera system for automatic visibility measurement, which can directly capture images of selected targets and their backgrounds through a digital camera, and then analyse and process them to obtain the value of visibility.

Factors Affecting Atmospheric Visibility

Atmospheric visibility is affected by a variety of factors, including the inherent brightness of the target and background, the brightness of the sky, and the optical properties of the atmosphere. For example, the higher the extinction coefficient in the atmosphere, the lower the visibility. In addition, visibility at night is different from that of daytime, which depends on the extinction characteristics of the atmosphere and the intensity of light.

Atmospheric visibility monitoring equipment

Modern technology has also developed a variety of visibility monitoring equipment, which can automatically monitor parameters such as visibility, wind direction, wind speed, temperature, humidity, atmospheric pressure, etc., and transmit the monitoring information to the monitoring centre in a timely manner to provide references for traffic control.

Conclusion

In summary, atmospheric visibility is a complex concept, which is affected by a variety of factors, and there are a variety of measurement methods and technical equipment to assess this parameter. Knowledge and understanding of the definition, measurement methods and influencing factors of atmospheric visibility are essential to ensure traffic safety and improve the visibility of various outdoor activities.