Moscow fell radiation fog

The morning of September 7, were greeted by a dense fog. Airports visibility deteriorated to 200-300 meters. Such conditions are considered below the minimum for take-off and landing aircraft.

Many are afraid of the definition of radiation fog. There is amateurish opinion is that radiation fog is related to the radiation. Some argue that it is formed over a uranium Deposit, while others believe that this is a result of radioactive fallout.

Indeed, yesterday in Moscow were heavy rains. Two days had one-third of the monthly norm of precipitation (22 mm). But the background radiation has not changed. Just dropped out the moisture and the ensuing erosion of clouds with nocturnal cooling were those necessary conditions under which is formed of radiation fog.

So why the fog is called radiation? The thing in the physical characteristics of the formation. On clear nights, when there is no "cloud blanket", the surface of the earth actively emits (hence the name radiation) heat into the atmosphere. While cooling and the surface and adjacent air layer. Cooling the air to a certain temperature begins condensation of water vapor and the formation of fog.

Usually radiation fogs occur at night or early in the morning, primarily in the lowlands. Favorable conditions for their formation is cloudless anticyclonic weather and light winds and the presence of a ground check of the layer — inversion. Factor contributing to the formation of fog, is the high concentration of airborne condensation nuclei (e.g., tiny particles of dust or soot).

With increasing air temperature and decreasing relative humidity, radiation fog dissipates. In the summer this usually occurs shortly after sunrise. In transitional periods, the fog can linger until about noon. In winter, with a small daily course of temperature, it may remain the whole day.

Translated by «Yandex.Translator»