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火龍捲：修订间差异

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小 机器人：修正双重重定向至烽火爆
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[[File:Fire-whirl.jpg|right|thumb|250px|A fire whirl with flames in the vortex]]
⚫
#重定向 [[烽火爆]]
'''火龍捲'''，又稱為'''火焰龙卷风'''、'''火焰漩涡'''<ref>{{cite news |url=photo.rednet.cn/space.php?uid=4852759&do=album&picid=381065 |title=美国农民焚烧农田现“火焰龙卷风”奇观 |date=2014-05-09 |accessdate=2014-05-11 |language=zh-hans }}</ref>、'''火災旋風'''等，是當空氣中的[[漩涡]][[亂流]]因為高熱及風向造成的湍流結合而形成，在旋風內有火焰。當這些[[渦旋]]空氣繼續收緊至類似[[龍捲風]]的結構時，可以吸入燃燒中的碎塊雜物及可燃氣體，從而使旋風點起火焰。

==形成==
火旋風有一個核心部分，實際上是由火和旋轉的空氣，不斷從外吸收新鮮的氧氣到其核心。一般的火龍捲核心，約莫0.30〜0.91米寬、15到30米高。在適當條件下可以形成大型的火龍捲，達十多公尺寬，超過300公尺高。火旋風的核心溫度可高達1,090℃，熱到足以使潛在重燃灰燼從地上吸起來。在通常情況下，這已經足夠可以變成火焰渦流或火龍捲。

對於大多數火龍捲來說，當其燃點起的地上植被釋放出來的可燃燒含碳量高氣體，能夠助長火龍捲。
即或這些氣體乃因為其他原因而透過燃燒被釋放出來，若然被空氣渦流吸入，當其身處環境一但能夠提供足夠及已達特定溫度的氧氣時，這些氣體就會立即點燃起火，從而形成了火龍捲那高高瘦瘦的核心部分。

現實世界的火旋風一般移動相當緩慢。火龍捲可以使其路徑上遇到的物體被點燃，也可以把燃燒中的碎片投擲到其周圍環境。由火龍​​捲引起的風也同樣危險：大型火龍捲引起的風，其風速可以超過{{convert|100|mph|km/h}}。這種風速的強度足以擊倒樹木。

火龍捲可以持續個多小時，而且往往不能直接撲滅<ref>Jason Fortofer (20 September 2012) http://news.nationalgeographic.com/news/2012/09/pictures/120920-fire-tornadoes-vortex-firenadoes-devils-science-weather/#/new-fire-tornado-spotted-australia_59442_600x450.jpg</ref>。

==例子==
During the [[2003 Canberra bushfires]], a fire tornado with a diameter of nearly {{convert|500|m|ft}} with horizontal winds exceeding {{convert|250|kph|mph}} was documented. Further research into the fires confirmed this in 2012.<ref>{{cite web |url=http://www.abc.net.au/news/2012-11-19/researchers-document-world-first-fire-tornado/4380252?WT.svl=news5 |title=Researchers document world-first fire tornado |author=Jessica Nairn |date=20 November 2012 |work=[[Australian Broadcasting Corporation]] |accessdate=20 November 2012}}</ref>
In [[Canberra]], wind damage consistent with an F3 tornado on the [[Fujita Scale]] was observed, in addition to the fire damage.<ref>McRae, >{{cite web |url=http://dx.doi.org/10.1007/s11069-012-0443-7 |title= An Australian pyro-tornadogenesis event. |author=McRae, R et al |date=1 October 2012 |work= [[Natural Hazards, Springer Netherlands]] |accessdate=20 November 2012}}</ref> New research released in 2013 showed that the [[supercell thunderstorm]] that caused the tornado originated from the converging winds of firestorm itself, one of the first confirmed observations of an intense thunderstorm forming from a [[Pyrocumulonimbus cloud]].<ref>{{cite web |url=http://www.abc.net.au/catalyst/stories/3774941.htm |title=Fire Tornado |author=
Anja Taylor |date=6 June 2013 |work=[[Australian Broadcasting Corporation]] |accessdate=6 June 2013}}</ref>

[[The Great Peshtigo Fire]] grew into a firestorm{{cn|date=January 2014}} which probably made one or several true tornadoes. Roofs were torn off the houses; even railway wagons were tossed around.

Another extreme example of a fire tornado from other than a vegetation fire is the [[1923 Great Kantō earthquake]] in [[Japan]] which ignited a large city-sized [[firestorm]]{{cn|date=January 2014}} and produced a gigantic fire whirl that killed 38,000 in fifteen minutes in the Hifukusho-Ato region of [[Tokyo]].<ref name="fire behavior">{{cite book |last=Quintiere |first=James G. |authorlink= |title=Principles of Fire Behavior |publisher=Thomson Delmar Learning |year=1998 |location= |isbn=0-8273-7732-0 }}</ref> Survivors' accounts of the nuclear bombing of Hiroshima also describe powerful fire whirls of tornadic proportions during the firestorm that followed the bombing.{{citation-needed|date=April 2014}}

Another example is the numerous large fire whirls (some tornadic) that developed after [[lightning]] struck an oil storage facility near [[San Luis Obispo, California|San Luis Obispo]], [[California]] on 7 April 1926, several of which produced significant structural damage well away from the fire, killing two. Thousands of whirlwinds were produced by the four-day-long{{dubious|date=January 2014}} firestorm{{cn|date=January 2014}} coincident with conditions that produced severe [[thunderstorm]]s, in which the larger fire whirls carried debris 5 kilometers away.<ref name="San Luis Obispo">{{cite journal |last=Hissong |first=J. E. |title=Whirlwinds At Oil-Tank Fire, San Luis Obispo, Calif. |journal=[[Monthly Weather Review]] |volume=54 |issue=4 |pages=161–3 |date=April 1926 | url=http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F1520-0493(1926)54%3C161%3AWAOFSL%3E2.0.CO%3B2 |doi=10.1175/1520-0493(1926)54<161:WAOFSL>2.0.CO;2 |format=abstract |bibcode = 1926MWRv...54..161H }}</ref>

==Classification==
There are currently three known types of fire whirls:<ref>{{cite web|title=The Occurrence and Mechanisms of Fire Whirls|url=http://www.seic09.eis.uva.es/Presentaciones/IL4.pdf|publisher=MAE UCSD; Spanish Section of the Combustion Institute|author=Williams, Forman|location=La Lolla, California; Valladolid, Spain|date=22 May 2009}}</ref>

*Type 1: Stable and centered over burning area.
*Type 2: Stable or transient, downwind of burning area.
*Type 3: Steady or transient, centered over an open area adjacent to an asymmetric burning area with wind.

There is evidence suggesting that the fire whirl in the Hifukusho-ato area, during the Great Kanto Earthquake of 1923, was of type 3.<ref>{{cite journal|last=Kuwana|first=Kazunori|coauthors=Kozo Sekimoto, Kozo Saito, Forman A. Williams|title=Scaling fire whirls|journal=Fire Safety Journal|date=May 2008|year=2008|month=05|volume=43|issue=4|pages=252–257|doi=10.1016/j.firesaf.2007.10.006|url=http://www.sciencedirect.com/science/article/pii/S0379711207001117|accessdate=30 January 2013}}</ref>

==References==
{{Reflist}}

==Sources==
* {{cite journal |last=Church |first=Christopher R. |authorlink= |coauthors=John T. Snow, and Jean Dessens |title=Intense Atmospheric Vortices Associated with a 1000 MW Fire |journal=[[Bulletin of the American Meteorological Society]] |volume=61 |issue=7 |pages=682–694 |date=July 1980 | url=http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F1520-0477%281980%29061%3C0682%3AIAVAWA%3E2.0.CO%3B2 |doi=10.1175/1520-0477(1980)061<0682:IAVAWA>2.0.CO;2 |format=abstract |bibcode = 1980BAMS...61..682C }}
* [http://fire.nist.gov/bfrlpubs/fire98/art079.html Fire Whirl Simulations]

==External links==
* http://vimeo.com/alicespringsfilmtv/skyfire/ Fire tornado video (whirl) 11 September 2012 Alice Springs Australia.
* [http://www.wunderground.com/wximage/viewsingleimage.html?mode=singleimage&handle=Photo5150&number=178&album_id=51&thumbstart=0&gallery=#slideanchor Photo]
* [http://www.abc.net.au/news/2012-11-19/researchers-document-world-first-fire-tornado/4380252 www.abc.net.au/news] Australian researchers document world-first fire tornado.
* [http://www.abc.net.au/catalyst/stories/3774941.htm Catalyst story: Fire Tornado]
*[http://uk.news.yahoo.com/setting-the-world-on-fire-stunning-pictures-of-rare-devil-tornado-emerge.html Another photo]
*[http://www.youtube.com/watch?v=ssn2kmNf0ME www.youtube.com] Video of a Fire whirl (0:30), Brazil.
* {{cite web |url=http://www.bbc.co.uk/news/world-latin-america-11086299 |title=Rare Footage of Fire Tornado |first= |last= |author= |authorlink= |date=25 Aug 2010 |year=2010 |work= |publisher=BBC |location= |page= |pages= |at= |language= |trans_title= |format= |doi= |archiveurl= |archivedate= |accessdate= |quote= |ref= |separator= |postscript= }}

[[Category:Wildfires]]
[[Category:Severe weather and convection]]
[[Category:Vortices]]
[[Category:Types of fire]]

[[fr:Tourbillon de poussière#Tourbillon de feu]]

'''烽火爆'''（{{lang|en|'''Firestorm'''}}）是一種經常出現在大範圍[[火災]]中的一種自然現象。
==成因==
由於大範圍的火災，其火場的分布相當多，火災範圍內的空氣流動加速，這也就造成了火場上空[[對流]]發展的空間；在一個可能成為旋風中心的有利地點，週遭的熱空氣不斷因燃燒而上升，而擠壓到了高空中的冷空氣持續向下填補，在兩者不斷的作用下，以及四周火場隔離開來的真空環境，形成了巨大的[[煙囪效應]]；這時只要一有外來的[[風]]力協助，這一個巨大的火災煙囪便會開始出現像渦輪般的旋轉。由人的肉眼去看，在旋轉中而形成的外觀很類似[[龍捲風]]，故而得名。
==災害==
火災旋風對人的傷害相當可怕，一個較大的火災旋風會釋放出可觀的[[煤氣]]，只要人身處火場四周，吸入火災旋風所產生的煤氣，將會造成呼吸器官的嚴重燒傷，最後窒息而死。

火災旋風的形成也造成撲滅大規模火災的困難，由於其火場擁有連鐵都能熔毀的高溫，因此對想要靠近火場的任何滅火行為都會造成一定的阻礙。
==相關==
火災旋風常出現在[[中心商務區|市中心]]的原因，可能與[[大廈風]]有關；因為最常出現火災旋風的[[山火]]，其形成的地理環境大半是在[[森林]]中，若把森林比喻為市中心四周的大樓，就能解釋其成因了。

==參看==
⚫
* [[烽火爆]]
*[[東京大空襲]] - [[德勒斯登轟炸]] - [[關東大地震]] - [[廣島原爆]]、[[長崎原爆]]

[[Category:火災]]
[[Category:自然現象]]

2014年5月10日 (六) 08:54的版本

A fire whirl with flames in the vortex

火龍捲，又稱為火焰龙卷风、火焰漩涡[1]、火災旋風等，是當空氣中的漩涡亂流因為高熱及風向造成的湍流結合而形成，在旋風內有火焰。當這些渦旋空氣繼續收緊至類似龍捲風的結構時，可以吸入燃燒中的碎塊雜物及可燃氣體，從而使旋風點起火焰。

形成

火旋風有一個核心部分，實際上是由火和旋轉的空氣，不斷從外吸收新鮮的氧氣到其核心。一般的火龍捲核心，約莫0.30〜0.91米寬、15到30米高。在適當條件下可以形成大型的火龍捲，達十多公尺寬，超過300公尺高。火旋風的核心溫度可高達1,090℃，熱到足以使潛在重燃灰燼從地上吸起來。在通常情況下，這已經足夠可以變成火焰渦流或火龍捲。

對於大多數火龍捲來說，當其燃點起的地上植被釋放出來的可燃燒含碳量高氣體，能夠助長火龍捲。 即或這些氣體乃因為其他原因而透過燃燒被釋放出來，若然被空氣渦流吸入，當其身處環境一但能夠提供足夠及已達特定溫度的氧氣時，這些氣體就會立即點燃起火，從而形成了火龍捲那高高瘦瘦的核心部分。

現實世界的火旋風一般移動相當緩慢。火龍捲可以使其路徑上遇到的物體被點燃，也可以把燃燒中的碎片投擲到其周圍環境。由火龍​​捲引起的風也同樣危險：大型火龍捲引起的風，其風速可以超過100英里每小時（160公里每小時）。這種風速的強度足以擊倒樹木。

火龍捲可以持續個多小時，而且往往不能直接撲滅[2]。

例子

During the 2003 Canberra bushfires, a fire tornado with a diameter of nearly 500米（1,600英尺） with horizontal winds exceeding 250公里每小時（160英里每小時） was documented. Further research into the fires confirmed this in 2012.[3] In Canberra, wind damage consistent with an F3 tornado on the Fujita Scale was observed, in addition to the fire damage.[4] New research released in 2013 showed that the supercell thunderstorm that caused the tornado originated from the converging winds of firestorm itself, one of the first confirmed observations of an intense thunderstorm forming from a Pyrocumulonimbus cloud.[5]

The Great Peshtigo Fire grew into a firestorm[來源請求] which probably made one or several true tornadoes. Roofs were torn off the houses; even railway wagons were tossed around.

Another extreme example of a fire tornado from other than a vegetation fire is the 1923 Great Kantō earthquake in Japan which ignited a large city-sized firestorm[來源請求] and produced a gigantic fire whirl that killed 38,000 in fifteen minutes in the Hifukusho-Ato region of Tokyo.[6] Survivors' accounts of the nuclear bombing of Hiroshima also describe powerful fire whirls of tornadic proportions during the firestorm that followed the bombing.Template:Citation-needed

Another example is the numerous large fire whirls (some tornadic) that developed after lightning struck an oil storage facility near San Luis Obispo, California on 7 April 1926, several of which produced significant structural damage well away from the fire, killing two. Thousands of whirlwinds were produced by the four-day-long[可疑] firestorm[來源請求] coincident with conditions that produced severe thunderstorms, in which the larger fire whirls carried debris 5 kilometers away.[7]

Classification

There are currently three known types of fire whirls:[8]

  • Type 1: Stable and centered over burning area.
  • Type 2: Stable or transient, downwind of burning area.
  • Type 3: Steady or transient, centered over an open area adjacent to an asymmetric burning area with wind.

There is evidence suggesting that the fire whirl in the Hifukusho-ato area, during the Great Kanto Earthquake of 1923, was of type 3.[9]

References

  1. ^ [photo.rednet.cn/space.php?uid=4852759&do=album&picid=381065 美国农民焚烧农田现“火焰龙卷风”奇观] 请检查|url=值 (帮助). 2014-05-09 [2014-05-11] （中文（简体））. 
  2. ^ Jason Fortofer (20 September 2012) http://news.nationalgeographic.com/news/2012/09/pictures/120920-fire-tornadoes-vortex-firenadoes-devils-science-weather/#/new-fire-tornado-spotted-australia_59442_600x450.jpg
  3. ^ Jessica Nairn. Researchers document world-first fire tornado. Australian Broadcasting Corporation. 20 November 2012 [20 November 2012]. 
  4. ^ McRae, >McRae, R; et al. An Australian pyro-tornadogenesis event.. Natural Hazards, Springer Netherlands. 1 October 2012 [20 November 2012]. 
  5. ^ Anja Taylor. Fire Tornado. Australian Broadcasting Corporation. 6 June 2013 [6 June 2013]. 
  6. ^ Quintiere, James G. Principles of Fire Behavior. Thomson Delmar Learning. 1998. ISBN 0-8273-7732-0. 
  7. ^ Hissong, J. E. Whirlwinds At Oil-Tank Fire, San Luis Obispo, Calif. (abstract). Monthly Weather Review. April 1926, 54 (4): 161–3. Bibcode:1926MWRv...54..161H. doi:10.1175/1520-0493(1926)54<161:WAOFSL>2.0.CO;2. 
  8. ^ Williams, Forman. The Occurrence and Mechanisms of Fire Whirls (PDF). La Lolla, California; Valladolid, Spain: MAE UCSD; Spanish Section of the Combustion Institute. 22 May 2009. 
  9. ^ Kuwana, Kazunori; Kozo Sekimoto, Kozo Saito, Forman A. Williams. Scaling fire whirls. Fire Safety Journal. May 2008, 43 (4): 252–257 [30 January 2013]. doi:10.1016/j.firesaf.2007.10.006.  已忽略未知参数|month=（建议使用|date=） (帮助);

Sources

External links

烽火爆（Firestorm）是一種經常出現在大範圍火災中的一種自然現象。

成因

由於大範圍的火災，其火場的分布相當多，火災範圍內的空氣流動加速，這也就造成了火場上空對流發展的空間；在一個可能成為旋風中心的有利地點，週遭的熱空氣不斷因燃燒而上升，而擠壓到了高空中的冷空氣持續向下填補，在兩者不斷的作用下，以及四周火場隔離開來的真空環境，形成了巨大的煙囪效應；這時只要一有外來的風力協助，這一個巨大的火災煙囪便會開始出現像渦輪般的旋轉。由人的肉眼去看，在旋轉中而形成的外觀很類似龍捲風，故而得名。

災害

火災旋風對人的傷害相當可怕，一個較大的火災旋風會釋放出可觀的煤氣，只要人身處火場四周，吸入火災旋風所產生的煤氣，將會造成呼吸器官的嚴重燒傷，最後窒息而死。

火災旋風的形成也造成撲滅大規模火災的困難，由於其火場擁有連鐵都能熔毀的高溫，因此對想要靠近火場的任何滅火行為都會造成一定的阻礙。

相關

火災旋風常出現在市中心的原因，可能與大廈風有關；因為最常出現火災旋風的山火，其形成的地理環境大半是在森林中，若把森林比喻為市中心四周的大樓，就能解釋其成因了。

參看

取自“https://zh.wikipedia.org/w/index.php?title=火龍捲&oldid=31248789”