Cirrus clouds are those pleasant thin, feather like, wispy like strands, comprised together with multiple tufts, that you see on a cool day. These clouds are usually no numerous that they are often indistinguishable from one another, thus forming a sheet called cirrostratus. Also at time convection that is at high altitudes produces another form of Cirrus clouds, cirrocumulus, which is a pattern of smaller tufts that are partially made up of super cooled water.
Cirrus clouds form the rising water vapour begins to freeze and forms into fine ice crystals at around 8,000 metres. Due to the scarcity of moisture at high altitudes, the clouds are in fact very thin. That is why aircraft travelling at this height or higher often leave Cirrus cloud formation, as the aircraft exhaust has a high water content which also freezes into ice crystals and leaves behind the easily recognisable straight aircraft trail lines. Eventually the ice crystals disappear as they fall and evaporate before reaching the ground.
The feather like characteristics of Cirrus clouds are filaments made up of heavier ice crystals, that tend to rain out. These falling streaks may indicate a difference in the motion air or turbulence between the upper part and the air below the clouds. The directions of winds emanating from these clouds can vary and can be tricky to predict as the top of the Cirrus clouds may be moving faster than the lower layers or vise versa, where an upper layer Sometimes the top of the cirrus cloud is moving rapidly above a intrudes on a faster moving lower layer.
Cirrus clouds act as an atmospheric filter to some degree. They have a high albedo, which means that only a certain amount of the solar radiation may reach the surface to warm it, while the rest is reflected back into space. At the same time Cirrus clouds trap infrared radiation in the form of heat. Thus allowing greenhouse gases to warm up the planet’s surface.
Due to large gaps in the scientific knowledge it is still unclear as to the exact effect that Cirrus clouds have on the moderation of the planet’s surface temperature. This in turn is due to high difficulty of being able to model the albedo of ever changing sizes of ice crystals and their distribution in the atmosphere. Faster computers and and deeper analysis will eventually be able to provide a better explanation of the phenomenon and thus provide better solutions in moderating the surface temperature.
However, there is enough meteorological data available that can be used to to predict an approaching frontal system or any upper atmospheric air disturbances from the formation of Cirrus clouds. For example, an increase in air traffic has had a positive effect on Cirrus clouds abundance. While, the surplus of the clouds accompany high altitude outflow of hurricanes (cyclones) and typhoons.
