Cloud species are a set of fourteen terms used to describe the shape and structure of clouds. Each one has its name abbreviated to a three letter term. Cloud species are identified and published in the International Cloud Atlas.
Species Abbreviation Description Genera Calvus cal Tops of clouds lose hard, rough appearance and become smooth Cb Capillatus cap Tops of clouds become distinctly fibrous or striated. Cirrus clouds are often in appearance Cb Castellanus cas Distinct turrets rising from a large base or line of cloud Sc, Ac, Cc Congestus con Great vertical height much larger than the base, shows vigorous growth with cauliflower like tops Cu Fibratus fib Fibrous appearance, with straight or uniform curves and no distinct hooks Ci, Cs Floccus flo Individual tufts of clouds with ragged bases and often with noticeable virga Ac, Cc, Ci Fractus fra Broken cloud with ragged bases and edges Cu, St Humilis hum Cloud with limited vertical height with a length much bigger than their height Cu Lenticularis len Lens or almond shaped clouds that are stationary in the sky Sc, Ac, Cc Mediocris med Clouds of moderate height that are around equal height and length, growing upwards Cu Nebulosus neb Featureless sheet of cloud with no structure St, Cs Spissatus spi Dense cloud appearing lighter shade of grey when viewed toward the sun Ci Stratiformis str Cloud in an extensive sheet or layer Sc, Ac, Cc Uncinus unc Distinctly hooked usually without a visible head Ci
References
See also List of cloud types
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