Visibility

See also: Visibility (homonymy)

In Meteorology, the visibility is the Distance to which it possible to see clearly, whatever the hour.

The visibility is important for all the forms of circulation: roads, navigation and aviation. The weather visibility refers to the transparency air: the visibility is thus independent of the presence of Lumière. In the field of the Aviation, several subclasses like the “visual range of track” (PVP) were defined.

In extremely clean air: into Arctic or in the mountains, the visibility can reach 70 to 100 kilometers. However, the visibility is often slightly reduced because of the Atmospheric pollution and strong the moisture.

Weather conditions reducing the visibility

In meteorology, one differentiates the Brume dries and the wet Brume. The elements which can reduce the visibility are:

the Fog
Smoked S, in particular at the time of forest fires
the sandstorms in the Deserted S
the blizzard
the Powder mill and the flurryes of snow.

Measure

Qualification

As example the French bulletins of marine weather uses the following scale.

See too

Sources

Weather France

atmospheric Prospect