In meteorology, a cloud is an aerosol consisting of a visible mass of minute liquid droplets, frozen crystals, or other particles suspended in the atmosphere of a planetary body or similar space. Water or various other chemicals may compose the droplets and crystals. On Earth, clouds are formed as a result of saturation of the air when it is cooled to its dew point, or when it gains sufficient moisture from an adjacent source to raise the dew point to the ambient temperature.
Cloud types in the troposphere, the atmospheric layer closest to Earth’s surface, have Latin names due to the universal adaptation of Luke Howard’s nomenclature. Formally proposed in 1802, it became the basis of a modern international system that divides clouds into five physical forms that appear in any or all of three altitude levels .These physical types, in approximate ascending order of convective activity, include stratiform sheets, cirriform wisps and patches, stratocumuliform layers , cumuliform heaps, and very large cumulonimbiform heaps that often show complex structures.
The Latin names for applicable high-level genera in the troposphere carry a cirro- prefix, and an alto- prefix is added to the names of the mid-level genus-types. Clouds with sufficient vertical extent to occupy more than one altitude level are officially classified as low- or mid-level according to the altitude range at which each initially forms. However they are also more informally classified as multi-level or vertical, which along with low level clouds, do not carry any altitude related prefixes.
However, due to their different temperature characteristics, they are often composed of other substances such as methane, ammonia, and sulfuric acid, as well as water.
The table should therefore be seen as an illustration of how the various cloud types are related to each other at all altitudes from surface-level to the “edge of space”, rather than as a strict classification per se.
