There are various kinds of cloud which might be identified visually in the atmosphere. These were classified by Lamarck from 1802, and Howard from 1803 released a classification strategy that became the foundation for contemporary cloud classification. The contemporary classification scheme used by the uk Met Office, with comparable schemes used everywhere, classifies clouds in accord with the elevation of cloud base, there being 3 elevation classes: low, mid level and high. Within every elevation class added classifications are described based on four basic types and mixtures thereof. These types are Cirrus, Stratus, Cumulus and Nimbus. Each main classification could be further subdivided to provide a way of identifying the numerous variations which are observed from the air.
The table below lists the conventional classifications employed by the uk Met Office and provides example pictures of each along with brief descriptions. Added to these main kinds there are a few other kinds of clouds such as noctilucent, polar stratospheric and orographic clouds. Some samples of many of those are given in the bottom of the table below. Often several kinds of cloud will be present at various levels of the setting at the same time. Table of Cloud Types – Low Level Cloud – Base is generally below 6, 500ft – These clouds generally form at altitudes between 1, 000 and 5, 000ft, although often temperature rises after creation result in a rise in cloud base height.
These clouds are usually formed by air rising as a consequence of surface heating and might occasionally produce light showers. Typically forms between the surface and 2, 000ft, but cloud base might be up to 4, 000ft. Thick stratus can produce considerable precipitation, especially in hilly or coast regions, though in several cases this precipitation can be falling from higher clouds like nimbostratus. While thick stratus will obscure sunlight or moon, they’re clearly visible through thin stratus. This cloud frequently occurs at altitudes between 1, 000 and 4, 000ft, though sometimes can be higher. While not usually producing precipitation these clouds might produce drizzle, especially in hilly or coast areas, and can be thick enough to obscure precisely the sun or moon.
These clouds consist entirely of liquid drops and are frequently formed close to precisely the top of precisely the planetary boundary layer. Cloud base is typically between 2, 000 and 5, 000ft, though in several cases this can be lower or higher. These clouds are formed when circumstances are such which deep convection is able to develop, and can have a big vertical extent especially in the tropics, occasionally reaching the tropopause. These clouds produce heavy showers, thunderstorms and hail, frequently also producing squally winds. At lower heights these clouds consist of liquid drops, but as elevation increases the cloud advances through mixed phase and completely icy conditions.