Cirrocumulus cloud

Cirrocumulus cloud
Cirrocumulus clouds on a summer afternoon
Abbreviation	CC[1]
Genus	Cirro- (curl of hair) -cumulus (heaped)
Altitude	Above 6000 m (20,000 ft)
Classification	Family A (High-level)
Appearance	Small, high, patched clouds, in rows[2]
Precipitation cloud?	Occasionally virga[2]
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Cirrocumulus clouds are one of the three main types of high-altitude clouds, which also includes cirrus clouds and cirrostratus clouds.^[3] They usually occur at an altitude of 5 kilometres (16,000 ft) to 12 kilometres (39,000 ft). Like other cumulus clouds, cirrocumulus clouds signify convection. Unlike other cirrus clouds, cirrocumulus include a small amount of liquid water droplets, although these are in a supercooled state. Ice crystals are the predominant component, and typically, the ice crystals cause the supercooled water drops in the cloud to rapidly freeze, transforming the cirrocumulus into cirrostratus. This process can also produce precipitation in the form of a virga consisting of ice or snow. Thus cirrocumulus clouds are usually short-lived.^[4]

Properly, the term cirrocumulus refers to each cloud, but is typically also used to refer to an entire patch of cirrocumulus. When used in this way, each cirrocumulus element is referred to as a "cloudlet".^[5]

Appearance

A cirrocumulus is typically a large, white patch or tuft without a gray shadow. Each cloudlet appears no larger than a finger held at arms length.^[4] It occurs in patches or sheets along with other cirrocumulus. These often are organized in rows like other cumulus, but since they are so small, cirrocumulus patches take on a finer appearance, sometimes also referred to colloquially as "herringbone" or "mackerel".^[1]

The cirrocumulus is distinguished from the not so similar altocumulus in several ways, although the two cloud types can occasionally occur together with no clear demarcation between them. Cirrocumulus generally occur at higher altitudes than altocumulus, and thus the "cloudlets" appear smaller as they are more distant from observation at ground level. They are also colder. Cirrocumulus clouds never cast self-shadows and are translucent to a certain degree. They are also typically found amongst other cirrus clouds in the sky, and are usually themselves seen to be transforming into these other types of cirrus.^[4]

Cirrocumulus clouds tend to reflect the red and yellow colors during a sunset and sunrise, and thus they have been referred to as "one of the most beautiful clouds".^[1][6] This occurs because they reflect the unscattered rays of light from the early morning or evening sun, and those rays are yellow, orange, and red.^[7]

References

Footnotes

1. ^ ^{a b c} Ahrens 2006, p. 120
2. ^ ^{a b} "Cirrocumulus Clouds". Cloud Microphysics Webpage. Georgia Tech University. http://nenes.eas.gatech.edu/Cloud/Clouds.pdf. Retrieved 6 February 2011. 
3. ^ Funk, Ted. "Cloud Classifications and Characteristics". The Science Corner. NOAA. http://www.crh.noaa.gov/lmk/soo/docu/cloudchart.pdf. Retrieved 6 February 2011. 
4. ^ ^{a b c} Prector-Pinney, p. 21
5. ^ "Cirrocumulus - Meteorology/Climate". Integration and Application Network. University of Maryland Center for Environmental Science. http://ian.umces.edu/imagelibrary/displayimage-search-0-6309.html. Retrieved 6 February 2011. 
6. ^ Palmer, Chad (October 16, 2005). "Cumulus clouds". USA Today. http://www.usatoday.com/weather/wcumulus.htm. Retrieved 6 February 2011. 
7. ^ Ahrens 2007, p. 98

Bibliography

• Pretor-Pinney, Gavin. The Cloud Collector's Handbook. ISBN 978-0-340-91943-9. 
• Ahrens, C. Donald (February 2006) (eBook). Meteorology Today: an Introduction to Weather, Climate, and the Environment (8 ed.). Brooks Cole. p. 120. ISBN 978-0-495-01162-0. http://books.google.com/books?id=SpGfKb23Y9QC&pg=PA120&lpg=PA120&dq=%2Bcirrocumulus+cloud#v=onepage&q=%2Bcirrocumulus%20cloud&f=false. Retrieved 6 February 2011. 
• Ahrens, C. Donald (January 2007). Essentials of Meteorology: An Invitation to the Atmosphere (5 ed.). Brooks Cole. pp. 97–99. ISBN 978-0-495-11558-8. http://books.google.com/books?id=2Yn29IFukbgC&pg=PA98&lpg=PA98&dq=%2Bcirrocumulus+cloud#v=onepage&q=%2Bcirrocumulus%20cloud&f=false. 

External links

• International Cloud Atlas - Cirrocumulus