What Kind of Cloud is That?
Wind-blown cumulus clouds (cumulus fractus, cumulus humilis, cumulus congestus)-Stokes Valley, Lower Hutt, N.Z.
CLOUD FORMATION AND NAMES Of CLOUDS
The study of clouds is one of the most fascinating aspects of meteorology, and even a person who has no knowledge of the physics behind cloud formation can derive immense pleasure from an examination of the infinite forms which clouds take.
Cloud forms clearly reflect the physical processes which are taking place in the atmosphere, and are therefore obvious indicators of weather conditions.
Briefly, clouds are caused mainly by the adiabatic cooling of air below its dew point; this cooling process is most effectively created by upward movements of air, which in turn produce reduction in pressure. The various types of cloud and their associated precipitation can then be accounted for largely by the various forms of upward motion, but clouds may be formed to a lesser degree by horizontal movement of air masses, and even rapid reducton of pressure:
Convection occurs in the atmosphere when it is heated at the earth's surface, either by being warmed in sunshine or when cool air flows into warmer regions. Large volumes of air rise from the surface layers and penetrate into and mix with the cooler air above, and once this rising air is cooled below its saturation point, the water in it condenses to form clouds.[cumulus type clouds]
Large cumulus congestus cloud build-ups. Stokes Valley, Lower Hutt, N.Z. [cloud tops around 12,000 ft - 14,000 ft]