澳大利亞野火引發(fā)罕見的天氣現(xiàn)象

澳大利亞野火引發(fā)罕見的天氣現(xiàn)象

Add fire-induced storms to the list of intense consequences from Australia's bushfires, as a wildfire season that began in October persists. Caused by several years of extremely dry conditions and hot summer temperatures (both exacerbated by climate change), occasional rain isn't enough to douse these flames — and won't, until autumn comes to the continent.

隨著10月份開始的野火季的持續(xù)，火災引發(fā)的風暴已經(jīng)成為澳大利亞森林大火的嚴重后果之一。由于連年的極度干旱和夏季的高溫(氣候變化加劇了這兩種情況)，偶爾的降雨不足以澆滅這些火焰——而且在秋季到來之前也不會。

Bushfires rage night and day, sometimes creating fire-induced storms and other weather conditions. (Photo: Daniel Mitchell/Shutterstock)

Thousands of people have evacuated from their homes along the eastern coast south of Sydney, 24 have died, and animals are racing to get out of harm's way. An area roughly the size of Denmark has burned, The New York Times estimates.

在悉尼南部的東海岸，成千上萬的人已經(jīng)從家中撤離，24人已經(jīng)死亡，動物們正在爭先恐后地逃離危險。據(jù)《紐約時報》估計，一塊面積與丹麥相當?shù)膮^(qū)域被燒毀。

The devastation is linked to the intensity of the fires, which are not just destroying bushlands and homes, but also causing local weather phenomena that have not been witnessed by humans at this scale.

這場災難與大火的強度有關(guān)，大火不僅摧毀了叢林和家園，還造成了人類從未見過的如此規(guī)模的當?shù)靥鞖猬F(xiàn)象。

In March 2016, this famous 'Hiroshima strike' photo was finally corrected. It shows a pyrocumulonimbus cloud caused by the massive fires several hours after the atomic bomb was dropped, not the bomb explosion itself. It was misidentified as such for decades. (Photo: U.S. military [public domain]/Wikimedia Commons)

One of the most visually dramatic fire creations are pyrocumulonimbus (sometimes abbreviated as pyroCb) clouds. They're formed by a massive source of heat — either a fire or sometimes a volcano, and NASA describes them as the "fire-breathing dragon of clouds."

最具視覺戲劇性的火災創(chuàng)造之一是火云(有時縮寫為pyroCb)。它們是由巨大的熱源形成的。它們是由大量的熱源形成的——有時是火，有時是火山，美國宇航局將它們描述為“噴火的云龍”。

"It's when a fire gets so big, and there's so much heat released, that the airmass from the fire rises vertically into the atmosphere, but really really deep, unlike most smoke plumes," Craig Clements, director of the San Jose State University Weather Research Lab explains. "To have so many at one time is unique. This is probably the largest outbreak of pyrocumulonimbus on Earth," says Clements.

圣何塞州立大學氣象研究實驗室主任克雷格·克萊門茨解釋說:“當火變得如此之大，釋放出如此多的熱量時，火的氣團垂直上升到大氣中，但真的非常非常深，不像大多數(shù)煙羽。一次擁有這么多是獨一無二的。這可能是地球上最大的一次火山噴發(fā)。”

Because the smoke punches so deep into the upper atmosphere, hitting as high as the tropopause (the barrier between the lower atmosphere and stratosphere), it can easily be seen from space. That smoke also travels, affecting those who live far from the fires — Sydney, Canberra and Melbourne have all had multiple days of unhealthy and hazardous breathing conditions.

由于煙霧深入高層大氣，到達對流層頂(低層大氣和平流層之間的屏障)，所以在太空中很容易看到。這些煙霧還會傳播，影響到那些遠離火災的人——悉尼、堪培拉和墨爾本都經(jīng)歷了多天的不健康和危險的呼吸狀況。

PyroCb clouds also cause massive thunderstorms, including lightning, which can cause more fires. These storms also create intense downdrafts as hot air pushes up into the atmosphere, causing fire tornadoes, and also causes embers from the fire to travel, creating yet more fires. These "ember attacks" are dangerous for any person or animal exposed to them — imagine small pieces of woody debris on fire and flying through the air.

PyroCb云也會引起大范圍的雷暴，包括閃電，這會引起更多的火災。這些風暴還會產(chǎn)生強烈的下沉氣流，因為熱空氣會向上推入大氣，引發(fā)火災龍卷風，還會導致火焰中的余燼移動，從而引發(fā)更多火災。這些“灰燼襲擊”對任何接觸到它們的人或動物都是危險的——想象一下木頭碎片著火并在空中飛舞。

During a recent ember attack, firefighters were able to take cover in their truck, and they told NBC News what it was like: "Everything was alight, both sides of the truck, the top — everything. It was like being in an oven."

在最近的一次余燼襲擊中，消防隊員得以在他們的卡車上尋找掩護，他們告訴NBC新聞:“所有東西都被點燃了，卡車的兩邊，頂部——所有東西。就像在烤箱里一樣。”