List of cloud types
Clouds of the genus stratus form in low horizontal layers having a ragged or uniform base. Ragged stratus often forms in precipitation while more uniform stratus forms in maritime or other moist stable air mass conditions. The latter often produces drizzle. Stratus that touches the Earth's surface is given the common name, fog, rather than a Latin name that applies only to clouds that form and remain aloft in the troposphere."Cloud types are sorted in alphabetical order except where noted".
The division of genus types into species is as shown in the following table. The species are sorted from left to right in approximate ascending order of instability or vertical extent. The genus types are arranged from top to bottom in the same ascending order of instability within each étage. (1)=Stratiform types, (2)=Cirriform types, (3)=Stratocumuliform types, (4)=Cumuliform types, (5)=Cumulonimbiform types.
Vert=Vertical or multi-level, MV=Moderate or deep vertical, TV=Towering vertical.
Cloud
Although the local distribution of clouds can be significantly influenced by topography, the global prevalence of cloud cover in the troposphere tends to vary more by latitude. It is most prevalent in and along low pressure zones of surface tropospheric convergence which encircle the Earth close to the equator and near the 50th parallels of latitude in the northern and southern hemispheres. The adiabatic cooling processes that lead to the creation of clouds by way of lifting agents are all associated with convergence; a process that involves the horizontal inflow and accumulation of air at a given location, as well as the rate at which this happens. Near the equator, increased cloudiness is due to the presence of the low-pressure Intertropical Convergence Zone (ITCZ) where very warm and unstable air promotes mostly cumuliform and cumulonimbiform clouds. Clouds of virtually any type can form along the mid-latitude convergence zones depending on the stability and moisture content of the air. These extratropical convergence zones are occupied by the polar fronts where air masses of polar origin meet and clash with those of tropical or subtropical origin. This leads to the formation of weather-making extratropical cyclones composed of cloud systems that may be stable or unstable to varying degrees according to the stability characteristics of the various airmasses that are in conflict.