Clouds take on many different shapes and sizes, endlessly changing combinations and positions in the sky. But despite the seeming chaos, there is a detailed system for categorizing them.
The International Cloud Atlas is the global standard for cloud classification. When a cloud does not fit any of the categories, a new one is introduced. In 2017, the World Meteorological Organization (WMO) added 12 new cloud types to the atlas.
The atlas uses the Latin naming system proposed by Luke Howard in 1803, which laid the foundation for its creation in 1939. The clouds are divided into ten main genera and are accompanied by information about their shape and height. For 79 years, the Cloud Atlas has been updated three times: in 1975, 1987, and most recently, in 2017.
What is the meaning of this work?
Clouds indicate the current state of the atmosphere, and cloud types are reported by meteorological observers around the world. It is important to have a complete and up-to-date cloud identification system for describing weather and climate. Atmospheric observatories have at least 100 years of long-term weather data that are used to monitor changes in our climate.
The infrequent atlas updates are mainly due to two reasons.
First, some of the newly classified clouds, such as Cirrus homogenitus, have not been encountered before. These clouds are airplane condensation trails, and their name means "cirrus anthropogenic". Thus, the additions to the Cloud Atlas show the human impact on the atmosphere.
Secondly, with the advent of smartphones, the possibilities for the discovery of new clouds have increased significantly - everyone can now watch and exchange photos of cloud formations. The Cloud Appreciation Society (CAS) has developed a special application that allows users to upload cloud images with their location data. An example of scientific discoveries made through the participation of civilian scientists is the recognition of Asperitas clouds as a distinct species in the latest edition of the atlas.
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