Dictionary of Geotourism

2020 Edition
| Editors: Anze Chen, Young Ng, Erkuang Zhang, Mingzhong Tian

Visibility

Reference work entry
DOI: https://doi.org/10.1007/978-981-13-2538-0_2671

Visibility is an index that reflects atmospheric transparency and is defined as the maximum distance that a person with normal vision can recognize a black target of a certain size from the background sky near the horizon. Visibility is divided into 10 levels; for example, 0 represents visibility of 0–50 m, 2 represents visibility of 200–500 m, 3 represents visibility of 500–1000 m, and 4 represents visibility of 1–2 km. Visibility is closely related to the weather conditions at the time of assessment. Poor visibility often occurs during rain or in foggy and hazy weather, storms or sandstorms.

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