Fallstreak hole: Difference between revisions
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A '''fallstreak hole''' (also known as a '''cavum''',<ref>{{cite news|last1=Sutherland|first1=Scott|title=Cloud Atlas leaps into 21st century with 12 new cloud types|url=https://www.theweathernetwork.com/news/articles/cloud-atlas-leaps-into-21st-century-with-12-new-cloud-types/80685/|accessdate=24 March 2017|work=The Weather Network|agency=Pelmorex Media|date=March 23, 2017}}</ref> '''hole punch cloud''', '''punch hole cloud''', '''skypunch''', '''cloud canal''' or '''cloud hole''') is a large gap, usually circular or elliptical, that can appear in [[cirrocumulus]] or [[altocumulus]] [[clouds]]. Such holes are formed when the water temperature in the clouds is below freezing, but the water, in a [[Supercooled water|supercooled state]], has not frozen yet due to the lack of [[ice nucleation]]. When [[ice crystals]] do form, a [[domino effect]] is set off due to the [[Bergeron process]], causing the water droplets around the crystals to evaporate: this leaves a large, often circular, hole in the cloud.<ref>{{Cite web|url=http://www.cloudappreciationsociety.org/74/|title=Cloud Appreciation Society {{!}} Fallstreak Holes (February '06)|website=cloudappreciationsociety.org|language=en-GB|access-date=2017-07-29}}</ref> |
A '''fallstreak hole''' (also known as a '''cavum''',<ref>{{cite news|last1=Sutherland|first1=Scott|title=Cloud Atlas leaps into 21st century with 12 new cloud types|url=https://www.theweathernetwork.com/news/articles/cloud-atlas-leaps-into-21st-century-with-12-new-cloud-types/80685/|accessdate=24 March 2017|work=The Weather Network|agency=Pelmorex Media|date=March 23, 2017}}</ref> '''hole punch cloud''', '''punch hole cloud''', '''skypunch''', '''cloud canal''' or '''cloud hole''') is a large gap, usually circular or elliptical, that can appear in [[cirrocumulus]] or [[altocumulus]] [[clouds]]. Such holes are formed when the water temperature in the clouds is below freezing, but the water, in a [[Supercooled water|supercooled state]], has not frozen yet due to the lack of [[ice nucleation]]. When [[ice crystals]] do form, a [[domino effect]] is set off due to the [[Bergeron process]], causing the water droplets around the crystals to evaporate: this leaves a large, often circular, hole in the cloud.<ref>{{Cite web|url=http://www.cloudappreciationsociety.org/74/|title=Cloud Appreciation Society {{!}} Fallstreak Holes (February '06)|website=cloudappreciationsociety.org|language=en-GB|access-date=2017-07-29}}</ref> |
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It is thought that the introduction of large numbers of tiny ice crystals into the cloud layer sets off this [[domino effect]] of [[Fusion power|fusion]] which creates the hole. The [[ice crystals]] can be formed by passing [[aircraft]], which often have a large reduction in pressure behind the [[Wing tip|wing-]] or propeller-tips. This cools the air very quickly, and can produce a ribbon of ice crystals trailing in the aircraft's [[Wake turbulence|wake]]. These ice crystals find themselves surrounded by droplets, and grow quickly by the Bergeron process, causing the droplets to evaporate and creating a hole with brush-like streaks of ice crystals below it. An early satellite documentation of elongated fallstreak holes over the [[Florida Panhandle]] that likely were induced by passing aircraft appeared in Corfidi and Brandli (1986).<ref>{{cite journal|last=Corfidi|first=Stephen|author2=Brandli, Hank|title=GOES views aircraft distrails|journal=National Weather Digest|date=May 1986|volume=11|pages=37–39|url=http://nwafiles.nwas.org/digest/papers/1986/Vol11-Issue2-May1986/Pg37-Corfidi.pdf}}</ref> Fallstreak holes are more routinely seen by the higher resolution [[Satellite|satellites]] of today (e.g., see |
It is thought that the introduction of large numbers of tiny ice crystals into the cloud layer sets off this [[domino effect]] of [[Fusion power|fusion]] which creates the hole. The [[ice crystals]] can be formed by passing [[aircraft]], which often have a large reduction in pressure behind the [[Wing tip|wing-]] or propeller-tips. This cools the air very quickly, and can produce a ribbon of ice crystals trailing in the aircraft's [[Wake turbulence|wake]]. These ice crystals find themselves surrounded by droplets, and grow quickly by the Bergeron process, causing the droplets to evaporate and creating a hole with brush-like streaks of ice crystals below it. An early satellite documentation of elongated fallstreak holes over the [[Florida Panhandle]] that likely were induced by passing aircraft appeared in Corfidi and Brandli (1986).<ref>{{cite journal|last=Corfidi|first=Stephen|author2=Brandli, Hank|title=GOES views aircraft distrails|journal=National Weather Digest|date=May 1986|volume=11|pages=37–39|url=http://nwafiles.nwas.org/digest/papers/1986/Vol11-Issue2-May1986/Pg37-Corfidi.pdf}}</ref> Fallstreak holes are more routinely seen by the higher resolution [[Satellite|satellites]] of today (e.g., see second example image in this article). |
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The articles by Westbrook and Davies (2010)<ref>{{cite journal|last=Westbrook|first=Chris|author2=Davies, Owain|title=Observations of a glaciating hole-punch cloud|journal=Weather|date=July 2010|volume=65|issue=7|pages=176–180|arxiv = 0907.4302 |bibcode = 2010Wthr...65..176W |doi = 10.1002/wea.504 }}</ref> and Heymsfield et al. (2010)<ref>{{cite journal |last1=Heymsfield |first1=Andrew J. |first2=Patrick C. |last2=Kennedy |first3=Steve |last3=Massie |first4=Carl |last4=Schmitt |first5=Zhien |last5=Wang |first6=Samuel |last6=Haimov |first7=Art |last7=Rangno |year=2010 |title=Aircraft-Induced Hole Punch and Canal Clouds: Inadvertent Cloud Seeding |journal=Bulletin of the American Meteorological Society |volume=91 |issue=6 |pages=753–766 |doi=10.1175/2009BAMs2905.1|bibcode = 2010BAMS...91..753H |doi-access=free }}</ref> explain the processes behind the formation of fallstreak holes in greater detail, and show some observations of their [[microphysics]] and [[Dynamics (mechanics)|dynamics]]. Such clouds are not unique to any one geographic area and have been photographed from many places. |
The articles by Westbrook and Davies (2010)<ref>{{cite journal|last=Westbrook|first=Chris|author2=Davies, Owain|title=Observations of a glaciating hole-punch cloud|journal=Weather|date=July 2010|volume=65|issue=7|pages=176–180|arxiv = 0907.4302 |bibcode = 2010Wthr...65..176W |doi = 10.1002/wea.504 }}</ref> and Heymsfield et al. (2010)<ref>{{cite journal |last1=Heymsfield |first1=Andrew J. |first2=Patrick C. |last2=Kennedy |first3=Steve |last3=Massie |first4=Carl |last4=Schmitt |first5=Zhien |last5=Wang |first6=Samuel |last6=Haimov |first7=Art |last7=Rangno |year=2010 |title=Aircraft-Induced Hole Punch and Canal Clouds: Inadvertent Cloud Seeding |journal=Bulletin of the American Meteorological Society |volume=91 |issue=6 |pages=753–766 |doi=10.1175/2009BAMs2905.1|bibcode = 2010BAMS...91..753H |doi-access=free }}</ref> explain the processes behind the formation of fallstreak holes in greater detail, and show some observations of their [[microphysics]] and [[Dynamics (mechanics)|dynamics]]. Such clouds are not unique to any one geographic area and have been photographed from many places. |
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Revision as of 14:57, 4 September 2020
A fallstreak hole (also known as a cavum,[1] hole punch cloud, punch hole cloud, skypunch, cloud canal or cloud hole) is a large gap, usually circular or elliptical, that can appear in cirrocumulus or altocumulus clouds. Such holes are formed when the water temperature in the clouds is below freezing, but the water, in a supercooled state, has not frozen yet due to the lack of ice nucleation. When ice crystals do form, a domino effect is set off due to the Bergeron process, causing the water droplets around the crystals to evaporate: this leaves a large, often circular, hole in the cloud.[2]
It is thought that the introduction of large numbers of tiny ice crystals into the cloud layer sets off this domino effect of fusion which creates the hole. The ice crystals can be formed by passing aircraft, which often have a large reduction in pressure behind the wing- or propeller-tips. This cools the air very quickly, and can produce a ribbon of ice crystals trailing in the aircraft's wake. These ice crystals find themselves surrounded by droplets, and grow quickly by the Bergeron process, causing the droplets to evaporate and creating a hole with brush-like streaks of ice crystals below it. An early satellite documentation of elongated fallstreak holes over the Florida Panhandle that likely were induced by passing aircraft appeared in Corfidi and Brandli (1986).[3] Fallstreak holes are more routinely seen by the higher resolution satellites of today (e.g., see second example image in this article).
The articles by Westbrook and Davies (2010)[4] and Heymsfield et al. (2010)[5] explain the processes behind the formation of fallstreak holes in greater detail, and show some observations of their microphysics and dynamics. Such clouds are not unique to any one geographic area and have been photographed from many places.
Because of their rarity and unusual appearance, fallstreak holes have been mistaken for or attributed to unidentified flying objects.[6]
Examples
-
Fallstreak hole over Ann Arbor, Michigan, November 14, 2016. -
Satellite image of canals and fallstreak holes over east Texas and Louisiana, January 2007 -
Fallstreak Hole over Naples, Italy, December 26, 2018 -
Fallstreak Hole over Oklahoma City, Oklahoma, January 2010 -
Fallstreak, Italy, Borso del Grappa, March 19th 2019
See also
References
- ^ Sutherland, Scott (March 23, 2017). "Cloud Atlas leaps into 21st century with 12 new cloud types". The Weather Network. Pelmorex Media. Retrieved 24 March 2017.
- ^ "Cloud Appreciation Society | Fallstreak Holes (February '06)". cloudappreciationsociety.org. Retrieved 2017-07-29.
- ^ Corfidi, Stephen; Brandli, Hank (May 1986). "GOES views aircraft distrails" (PDF). National Weather Digest. 11: 37–39.
- ^ Westbrook, Chris; Davies, Owain (July 2010). "Observations of a glaciating hole-punch cloud". Weather. 65 (7): 176–180. arXiv:0907.4302. Bibcode:2010Wthr...65..176W. doi:10.1002/wea.504.
- ^ Heymsfield, Andrew J.; Kennedy, Patrick C.; Massie, Steve; Schmitt, Carl; Wang, Zhien; Haimov, Samuel; Rangno, Art (2010). "Aircraft-Induced Hole Punch and Canal Clouds: Inadvertent Cloud Seeding". Bulletin of the American Meteorological Society. 91 (6): 753–766. Bibcode:2010BAMS...91..753H. doi:10.1175/2009BAMs2905.1.
- ^ 'UFO cloud formation' filmed in Romania
External links
Wikimedia Commons has media related to Cavum (meteorology).
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