Stratus
In Meteorology, a stratus (abbreviation St) is a Nuage low whose base is with Altitude S lower than a few hundred meters. When this base touches the ground, that corresponds to Brouillard.
The stratus generally has a rather uniform aspect (stratus nebulosus) but sometimes consists of separate elements having a shredded aspect (stratus fractus). The stratus is often accompanied by a misty atmosphere , and has a characteristic color grisâtre. One uses sometimes the generic term “greyness”, which includes at the same time the fogs, the fogs, and the clouds very low (stratus, to see Stratocumulus). The stratus (with the fog) is the only cloud likely to give Bruine (precipitation of very fine water droplets, also called drizzle), or when the Température is under 0° Celsius, of snow in grain (very fine particles of ice of diameter lower than a millimetre).
Formation
The strati appear when the very low layers of the atmosphere are very wet. The causes of formation of the strati are the same ones as in the case of the formation of the fog (night cooling, contribution of humid air coming from a lake, a sea or an ocean, evaporation with the top of a stretch of water or strong rain). The strati can also result from the evolution of the fogs (of which the base rises thanks to the warming of the ground after the rising of the sun), or more rarely of the evolution of Stratocumulus (by lowering or standardization of the base). When they are not very thick, the strati which were formed in the night become stratus fractus and are dissipated quickly at the beginning of day. But when they are thicker, for example in anticyclonic conditions the winter, it may be that the Sun does not arrive by boring, and the low clouds, sometimes even the fog, persist all the day. Even if time remains gray, the thin warming of the ground in day is sometimes sufficient to heat, and thus to drain a little the lowest layers of the atmosphere. The stratus is transformed then gradually into stratocumulus.
| Random links: | Saint-Thibault-of-vines | El Tajín | Route main road 802 | Nora Lafi | Matteson,_l'Illinois |